Peritectic titanium alloys for 3D printing

Metal-based additive manufacturing (AM) permits layer-by-layer fabrication of near net-shaped metallic components with complex geometries not achievable using the design constraints of traditional manufacturing. Production savings of titanium-based components by AM are estimated up to 50% owing to the current exorbitant loss of material during machining. Nowadays, most of the titanium alloys for AM are based on conventional compositions still tailored to conventional manufacturing not considering the directional thermal gradient that provokes epitaxial growth during AM. This results in severely textured microstructures associated with anisotropic structural properties usually remaining upon post-AM processing. The present investigations reveal a promising solidification and cooling path for α formation not yet exploited, in which α does not inherit the usual crystallographic orientation relationship with the parent β phase. The associated decrease in anisotropy, accompanied by the formation of equiaxed microstructures represents a step forward toward a next generation of titanium alloys for AM.

The authors report on a new Ti-base alloy for additive manufacturing (AM, also referred to as 3D printing). Even if AM already is used in industry for realization for complex components, numerous upon questions/issues remain. One major roadblock to more widespread applications is the limited number of alloys being available to be processed employing powder bed techniques such as selective laser melting (SLM). Most importantly, alloys employed so far have been developed for conventional processing routes, e.g. forging and casting. Thus, these alloys are not adapted to the unique processing conditions prevailing in AM and SLM, respectively. Rapid solidification and epitaxial growth are two aspects to be mentioned in this regard. In the field of Ti-base alloys, almost exclusively Ti-6Al-4V and commercial purity (CP) titanium are considered in both academia and industry. It is well accepted that these alloys suffer from several process-induced issues: anisotropic microstructure and mechanical properties as well as low damage tolerance. Thus, post treatments always need to be conducted. Still, the anisotropic nature of deformation prevails upon standard post processing routes.
In consequence, development of new Ti-alloys meeting the process conditions of AM and SLM, respectively, and allowing for realization of isotropic microstructures are crucially needed for further development in the field. By adding La to CP titanium the authors address this topic in an excellent way. Results obtained are of highest quality and were elaborated using absolutely sophisticated characterization techniques, e.g. high-energy X-ray diffraction (HEXRD). Conclusions drawn based on data presented are fully convincing. The general idea of adapting Ti-alloys to AM by using a peritectic reaction is absolutely novel and will open up windows for target oriented alloy design in other alloy systems as well. The thorough experimental effort, quality of data, in-depth discussion and expected impact of the approach presented are clearly up to the standard of Nature Communications. Quality of figures and text and, thus, presentation of results is excellent.
In consequence, the reviewer strongly recommends acceptance of the current work.
In order to further strengthen their contribution, the authors should consider the following (not mandatory): In the introduction section, numbers provided should be substantiated. Production savings up to 50% are highlighted. Which kind of components are referred to here? Furthermore, additional references to current literature could be provided. Realization of isotropic microstructures in Al-alloys as well as steels has been published quite recently: use of nano-sized particles for grain refinement in high-strength aluminium alloys and employment of multiple phase transformations induced by intrinsic heat treatment in high alloyed steels. These concepts should be introduced shortly in the introduction section even if not being applicable to Ti-base alloys so far. The authors should plot the binary phase diagram in a way that allows highlighting eutectic, peritectoid and eutectoid reaction in the system. Cost for the element La should be provided. Some details mentioned in the text (e.g. agglomerations of alpha´ plates (page 5, line 98)) cannot directly be seen in the corresponding figures. The authors should add further markers to highlight these features. The authors should consider showing (part of) the phase diagram for the ternary Ti-Fe-La system in the supplement. When discussing results shown (or in the corresponding part of the methods section) clear statements on number of samples and sample volume probed have to be provided. Using powder blends for AM always opens up the following questions: What are the characteristics of all powders employed (details on La and Fe powders are missing). Using which apparatus the powders were mixed? Are all samples processed homogeneous in terms of chemical composition? Regarding SLM processing the following questions should be answered: Is any information on element evaporation available? What size of build envelope was employed? Is there any information on gas flow? Scale bars in Figure 2 remain unclear: Scale bars of 100 microns and 50 microns seem to be valid for c and d, respectively. The overall size of both figures is very similar. The boxes highlighting the areas depicted in high resolution at the bottom are clearly different in size in the overview images. Thus, the same scale bar cannot be correct for c and d. Please clarify. Finally, showing a stress-strain curve from tensile testing would be very helpful to draw a complete picture of the new material processed. Are data available?
Reviewer #3 (Remarks to the Author): This is a well-written paper with an interesting result, namely that La can be useful for changing the solidification (phase) path in titanium. I appreciate the use of synchrotron x-ray diffraction experiments to complement the microstructural characterization. Unfortunately, justifying publication in Nature Communications on the basis of mitigating strong texture in typical additively printed Ti-6Al-4V is not supported by the literature because, in fact, the texture in the dominant (~90 %) alpha phase is weak; see, e.g., A. A. Antonysamy, J. Meyer, and P. B. Prangnell, Effect of build geometry on the beta-grain structure and texture in additive manufacture of Ti-6Al-4V by selective electron beam melting, Materials Characterization, 84, 153-168 (2013). That the texture is weak is unsurprising because when the strongly columnar (bcc) beta transforms to (hexagonal) alpha following the Burgers orientation relationship, the high driving force available under rapid cooling means that there is negligible variant selection and the texture in the alpha is weak. Also, martensitic structures can be easily reverted to two-phase via heat treatment which is generally done if for no other reason than stress relief, especially in laser powder bed materials. A second criticism concerns the interpretation of the tortuous grain shapes that were observed: the authors need to read the literature on 3D printing and check what scan strategy was used in their particular builds because it can happen that offsets and changes in direction force the direction of the thermal gradient (and therefore the solidification path) to change substantially from layer to layer, resulting in the observed pattern. By contrast, scanning in the same direction in successive layers with no offset in lateral position can result in very strong epitaxial growth. This means that texture is at least as much influenced by scan strategy as by local solidification conditions. I apologize for not offering more detailed feedback but the authors need to re-think the basis for the originality of their work.
which the microstructure is observed to be more equiaxed in nature following additive manufacturing. The Ti-La system is generally a under explored binary system.
The general concept of breaking up texture in additively manufactured titanium alloys is of broad interest to the community, and has been the subject of several papers over the past few years, and related to grain size in titanium alloys in general. In particular, the previous use of boron has been reported to have a strong influence on reducing both texture (as represented by the multiple times random distribution of the orientation data) and grain size. The authors are encouraged to consider adding a reference to this work (e.g., "The effect of boron on the grain size and texture in additively manufactured β-Ti alloys." Journal of Materials Science 52, no. 20 (2017): 12455-12466.). This is by no means a requirement, but the authors may find some interesting future opportunities, as there has been speculation in the literature about whether boron disrupts the Burgers orientation relationship. The reviewer is aware of other work that has investigated additions of Fe as well.
Indeed, previous investigations modified the chemical composition of titanium alloys for additive manufacturing (AM) by addition of B and Fe. Similarly to the problematic presented in our work, these approaches aim at tackling epitaxial growth in AM-produced titanium alloys, reporting remarkable advances. The authors acknowledge the contribution of the reviewer, and would like to cordially refer her/him to the introduction of the resubmitted manuscript.  fig. 5g analyzed by EBSD, as there is a sufficient volume fraction beta).
The new figure " Supplementary Fig. 5" has been included in the resubmitted version of the manuscript in order to provide robustness to the evidence of the non-Burgers orientation relationship in the Ti-1.4Fe-1La system. New EBSD analyses have been performed. Following the reviewer's suggestion, evidence of non-operating Burgers relationship is now provided for 3 different locations considering adjacent  regions. Moreover, this effect is also presented for the complete studied area: "Accordingly, the bi-modal distribution of lattice correlation boundaries between  and  phases obtained by EBSD for this condition (Fig. 5h), shows the presence of two distinct paths of  formation:  formed via the Burgers OR and non-Burgers OR  derived from the path L 1 +  . Moreover, Supplementary Fig. 5 provides further crystallographic evidence of non-operating Burgers relationship in the heat treated Ti-1.4Fe-1La alloy by considering adjacent - regions."

C3.
Here are a few comments that the authors may consider which may improve their overall paper: * (Lines 51-59) The authors refer to martensitic structures in titanium as "brittle". I concur that generally they may be less ductile than pure titanium or many alloys. However, this is not intrinsically the same as "brittle" in the martensitic transformation in steels, as the crystal structure is simply a supersaturated hcp (or orthorhombic The authors agree with the points raised by the reviewer. Following her/his suggestion, a broader explanation is included in the new version of the text clarifying the different causes of brittleness occurring in steels and titanium alloys containing martensite. As this phase is usually obtained upon AM of + titanium alloys, providing poor ductility and fracture toughness, this additional description requested in the introduction will offer a better understanding of the goal pursued by our investigations. Moreover, the lack of specification referencing the post processing of martensitic microstructures has been corrected in the resubmitted version, supported by the following new key references:  Page 7, lines 152172: "Columnar-to-equiaxed transition (CET) of grain formation has been related to spatial-temporal variations in the thermal gradient (G) and solidification rate (R) as presented in G-R solidification maps 31 . These terms strongly depend on local composition, which is governed by liquid/solid interfacial instabilities (e.g. constitutional undercooling, CU) 17,31 . For the hierarchical microstructure shown in Fig. 2d, CU may be able to provide the necessary driving force for grain nucleation leading to regions with fine equiaxed grains. It seems plausible to suggest that CU variations can take place locally in heat-affected regions promoting the formation of fine equiaxed  grains: cyclic re-melting of previously deposited material may improve the compositional homogeneity of the Ti-2La powder blend, and create new nuclei via CU. The low solubility of La in -Ti and -Ti may as well contribute to a large CU 28 . Although columnar grain growth is observed in In the resubmitted version of the manuscript, the authors have included the exact value following the reviewer's request: Page 9, lines 195197: "As the temperature decreases, a rapid transformation    leading to ~95vol.% of  in ~ 3.7 min takes place between 900-850°C." This calculation is derived from the evolution of the volume fraction of  as a function of a time presented in Supplementary Fig.4.
In order to avoid possible misleading from the previous description, the quenching conditions pointed by the reviewer have been clarified in the new version of the manuscript: Page 10, lines 206-209: "Metallographic analysis of the SLM Ti-2La alloy quenched from 950°C (L 1 + field) down to RT (Methods), with a cooling rate of ~ 85°C/s between 950350°C, is shown in Fig. 4d."

C10. * Lines 157-158: The authors use pole figures and multiple of random distribution (MRD) values to
underpin their argument that the Burgers OR is not adopted. There is insufficient evidence that this is true. E.g., Fig. 2 (a,b) show a mrd of 2.4 and 1.9, with hot spots in similar locations. Arguably, this may be a 30-35% reduction in texture, but clearly the Burgers OR is still active. Traditional evidence would include TEM microscopy (or higher resolution EBSD), and ultimately, the authors would be more able to convincingly prove that this is true.
The lines referred here are also pointed by the reviewer in her/his comment C5 (Reviewer#1), where the incorporation of a new figure (Supplementary Fig. 3) providing traditional evidence of possible non-occurrence of the Burgers OR in the Ti-2La system has been presented. The reviewer is cordially referred to this modification as well as to the other new figure added " Supplementary Fig. 5", which also provides further evidence that a non-Burgers OR can take place in the Ti-1.4Fe-1La system (comment C2 of Reviewer#1). The authors agree with the statement of the reviewer pointing that the Burgers OR is still partially active, and therefore, two distinct paths of  formation are observed:  formed via the Burgers OR and non-Burgers OR  derived from the path L 1 +  . Thus, the text has been modified accordingly for both Ti-La and Ti-1.4Fe-1La systems: Page 11, lines 227234: Owing to the modifications introduced in the resubmitted version of the manuscript, pointed in comment C6 of Reviewer #1, the terminology "constitutional undercooling" is now used several times in the text. Thus, its abbreviation "CU" has been incorporated in the resubmitted text for referring this term after its first use in page 8 line 155. Moreover, the significance of our investigations has been better contextualized in the resubmitted text following the suggestion introduced by Reviewer #2 in comment C1:

C13. * Line
"The general idea of adapting Ti-alloys to AM by using a peritectic reaction is absolutely novel and will open up windows for target oriented alloy design in other alloy systems as well." The following paragraph has been modified in accordance with the inputs of Reviewer #1 and Reviewer #2:

Quality of figures and text and, thus, presentation of results is excellent.
In consequence, the reviewer strongly recommends acceptance of the current work.
In order to further strengthen their contribution, the authors should consider the following (not mandatory): In the introduction section, numbers provided should be substantiated. Production savings up to 50% are highlighted.
Which kind of components are referred to here?
The reviewer refers to lines 3739 of the previous version the manuscript. There, it was vaguely mentioned that the advantages of AM titanium-based components account for "estimated production savings up to 50%, by missing out in major part, exorbitant machining costs and material loss 3 ".  (2013)). These modifications have been incorporated in the text as follows: Page 3, lines 3750: "For titanium-based components, these advantages account for estimated production savings up to 50%, by missing out in major part, exorbitant machining costs and material loss 3 . In aerospace, AM of titanium components focuses on parts with high buy-to-fly ratio: the weight of purchased stock material with respect to that of the finished part. Typical aerospace components can have 10:1, 20:1, and even 40:1 buy-to-fly ratios using conventional manufacturing processes. AM is capable to reduce it to close to 1:1. For instance, 50% reduction of the production costs has been reported for a conventionally fabricated wrought Ti-6Al-4V engine bracket using AM 4 . AM also allows repair of expensive titanium-based components (e.g. flanges, fan blades, casings, vanes and landing gears) at 20-40% of the cost of the new parts 1 . Beyond the manufacturing chain, AM weight-optimized components can imply a progress of environmental targets.
Previous studies concluded that savings of 3.3 million litres of fuel over the aircraft's life can be obtained by a weight reduction of 55% using AM Ti-6Al-4V seat buckles 1 ."

C2. Furthermore, additional references to current literature could be provided. Realization of isotropic microstructures in Al-alloys as well as steels has been published quite recently: use of nano-sized particles for grain refinement in high-strength aluminium alloys and employment of multiple phase transformations induced by intrinsic
heat treatment in high alloyed steels. These concepts should be introduced shortly in the introduction section even if not being applicable to Ti-base alloys so far.
We have added new citations reporting advances in tackling epitaxial growth of AM alloys aiming at better contextualization. This includes slight modification of the chemical composition of Ti-alloys. The reviewer is cordially referred to the comment C1 of Reviewer #1 where incorporation of this research in the manuscript is presented. Since this is not the only strategy, and as the reviewer correctly points, this subject of study requires a broader perspective of analysis, new insights using the intrinsic heat treatment as well as nanoparticles in different materials (e.g. steel, aluminium) have also been introduced in the text.   Table 1 with the transformations identified in situ using high energy synchrotron X-ray diffraction. It must be emphasized that investigation of the Ti-La phase diagram is not the focus of our work, and the data presented in the manuscript is based on other works 28,29 , not on own investigations.
Supplementary Fig. 1 a Portion the Ti-La phase diagram and b magnified detail of the studied region adapted from 28,29 , indicating the compositions used for selective laser melting.
Incorporation of the new Supplementary Fig. 1 has been pointed in the resubmitted text: Page 6, lines 122-126: "According to the current knowledge of the Ti-La equilibrium phase diagram (shown partially in Fig. 1a and Supplementary Fig. 1), at 2wt.% La the Ti-La system presents during cooling two paths of  formation after passing through a L 1 +  La-bcc peritectic reaction 28 : La-bcc+   (peritectoid) and La-bcc  La-fcc+ (eutectoid)."

C4. Cost for the element La should be provided.
The cost of La powder used in our investigations has been included in the resubmitted version of the manuscript. It is worth noting that the price strongly varies depending on the element form (e.g. powder or pieces). This is reflected in the diagram provided below obtained from the CES Edupack 2017 software, where the price of La is presented with respect to commonly used alloying elements in titanium. For instance, La can be significantly cheaper than V, alloying element of the most commercialized Ti alloy Ti-6Al-4V. This reference has been included in the resubmitted manuscript. Thus, reduction of the cost impact of La via ingot metallurgy can be expected, i.e. the use of ingot-based powder alloys instead of powder blending for additive manufacturing may be more economically viable.  Fig. 2 can be observed. The new indication is reflected in the resubmitted text: Page 7, lines 148151: "Minor agglomerations of  plates can also be seen as pointed by arrows in the magnified region of Fig.   2d (see Fig. 2e). Arrangements of fine  grains can be observed between layers of elongated  grains marked between discontinuous lines in Fig. 2d." C6. The authors should consider showing (part of) the phase diagram for the ternary Ti-Fe-La system in the supplement.
The authors would like to point that the ternary Ti-Fe-La is an unusual system, as mentioned by The authors would like to kindly refer the reviewer to comment C11 of Reviewer #1, where compositional homogeneity during in situ alloying of powders during SLM has been discussed by linking the SLM scanning strategy employed with a new figure provided. In addition to this, the information requested by the reviewer, namely the characteristics of powders and blending process, has been included in the resubmitted text: Page 16, lines 344355: "The alloys were produced by blending base powder of CP Ti with additions of commercial powder of pure La (99.9%) and Fe (>99%) elements with maximal and mean particle sizes of ~74µm and ~3.5µm, respectively. Powder blending was performed inside stainless steel containers within a glovebox kept in an atmosphere of argon 5.0 of purity and <1ppm of oxygen content. Thereafter, flowability tests were successfully carried out employing a stand Ti-6Al-4V funnel for testing free-flowing metal powder according to ISO 4490:2001. The containers of ~ 12kg of powder capacity were tightly sealed by using a valve inside the glovebox. By doing so, they were prepared to be placed in the SLM machine.
The SLM equipment was supplied by SLM solutions GmbH, CP Ti powder produced by gas atomization by TLS Technik Gmbh, La (packaged in Ar atmosphere) and Fe powders by Alfa Aesar and BASF CEP SM, respectively."

C9 .Regarding SLM processing the following questions should be answered: Is any information on element evaporation available? What size of build envelope was employed? Is there any information on gas flow?
There is no experimental data available about material evaporation during SLM. However, a critical role of this effect is not expected compared to Ti-6Al-4V, since the energy density employed (175J/mm 3 ) in our investigations is within those being used for this alloy (e.g. The authors appreciate the reviewer's careful assessment, and would like to refer him to the new Fig. 2, where the size of the boxes indicating the magnified regions has been corrected:

C11. Finally, showing a stress-strain curve from tensile testing would be very helpful to draw a complete picture of the new material processed. Are data available?
Data on mechanical testing is unfortunately unavailable yet. We are well aware of the significance of such information. However, this would require the production of much larger samples, which is planned for a further project on these alloys and for which we are waiting for funding. We will certainly present mechanical testing data in future investigations.

Reviewer #3 (Remarks to the Author):
C1. This is a well-written paper with an interesting result, namely that La can be useful for changing the We have to emphasize this issue: texture mitigation in Ti-alloys produced by additive manufacturing is a very timely and relevant matter, both from a technical and scientific point of view. We take here the liberty of quoting some comments given by the other reviewers of our work: Please note that we have even included the reference pointed by the reviewer in which texture in  is clearly shown. We reproduce here the pole figures of  and  presented in this work, reference 5 of our manuscript (it must be mentioned that the pole figure of  was calculated and not measured experimentally): The texture of  is clearly visible and corresponds to the typical texture observed owing to epitaxial growth and Burgers OR in AM Ti alloys. Moreover, the authors of this publication write in section 3.2.2: "In general, the -transformation textures were far weaker than their reconstructed β-parent textures and had a maximum intensity of only ~3 times random in bulk sections, compared to 8 times random seen for the parent β-texture." It is evident that the authors are comparing the pole figures of  and  and therefore, they mention that texture of  is weaker than that of , i.e. from a relative point of view to the parent phase, which is related to the nature of the  to  transformation in Ti alloys, or, as the authors put it: "Because of crystal symmetry, this provides 12 possible variant orientations that can form from a single parent β-grain, which if randomly selected will dilute the texture compared to the β-solidification texture." Again, they compare the texture between  and  and, while it can be argued that the texture of  is weaker than that of  it must certainly be said that  is still strongly textured and this agrees with the results shown in the mentioned paper (and in many of the reports given in the list above).
Therefore, we disagree with the argumentation of the reviewer and kindly ask her/him to reconsider her/his position.

C2. Also, martensitic structures can be easily reverted to two-phase via heat treatment which is generally
done if for no other reason than stress relief, especially in laser powder bed materials.
The aspect pointed by the reviewer has been discussed in the resubmitted version of the The criticism introduced by the reviewer has been also discussed in the resubmitted version of the manuscript by taking into account the support of the literature and the helpful contribution of Reviewer 1. This is clarified in comment C6 of Reviewer 1, to which the reviewer is kindly referred.
At last, the authors would like to thank the reviewers for careful reading of the manuscript and the provision of their constructive comments.

REVIEWERS' COMMENTS:
Reviewer #1 (Remarks to the Author): Thank you for the careful attention to the reviewers comments.
Reviewer #2 (Remarks to the Author): The authors report on a new Ti-base alloy for additive manufacturing (AM, also referred to as 3D printing). Even if AM already is used in industry for realization for complex components, numerous upon questions/issues remain.
One major roadblock to more widespread applications is the limited number of alloys being available to be processed employing powder bed techniques such as selective laser melting (SLM). Most importantly, alloys employed so far have been developed for conventional processing routes, e.g. forging and casting. Thus, these alloys are not adapted to the unique processing conditions prevailing in AM and SLM, respectively. Rapid solidification and epitaxial growth are two aspects to be mentioned in this regard. In the field of Ti-base alloys, almost exclusively Ti-6Al-4V and commercial purity (CP) titanium are considered in both academia and industry. It is well accepted that these alloys suffer from several process-induced issues: anisotropic microstructure and mechanical properties as well as low damage tolerance. Thus, post treatments always need to be conducted. Still, the anisotropic nature of deformation prevails upon standard post processing routes.
In consequence, development of new Ti-alloys meeting the process conditions of AM and SLM, respectively, and allowing for realization of isotropic microstructures are crucially needed for further development in the field. By adding La to CP titanium the authors address this topic in an excellent way. Results obtained are of highest quality and were elaborated using absolutely sophisticated characterization techniques, e.g. high-energy X-ray diffraction (HEXRD). Conclusions drawn based on data presented are fully convincing. The general idea of adapting Ti-alloys to AM by using a peritectic reaction is absolutely novel and will open up windows for target oriented alloy design in other alloy systems as well.
The thorough experimental effort, quality of data, in-depth discussion and expected impact of the approach presented are clearly up to the standard of Nature Communications. Quality of figures and text and, thus, presentation of results is excellent. In consequence, the reviewer strongly recommends acceptance of the current work in its revised version.
Reviewer #3 (Remarks to the Author): I appreciate the effort that the authors have made to respond to the feedback and improve the manuscript. I have not changed my mind about whether it belongs in Nature Comm. because it does not. Instead it should go to one of the metallurgical journals. The discussion of texture and anisotropy is naive. Yes there is anisotropy but it is a second order problem. The texture of the alpha is not strong, precisely because of the martensitic phase transformation and formation of multiple variants. Heat treatments of martensitic Ti alloy can yield impressive ductility, see the work by Charlotte de Formanoir, e.g. Rejection is recommended.

Reviewer #1 (Remarks to the Author):
C1. Thank you for the careful attention to the reviewers comments.

Reviewer #2 (Remarks to the Author):
C1. The authors report on a new Ti-base alloy for additive manufacturing (AM, also referred to as 3D printing). We have to emphasize this issue: texture mitigation in Ti-alloys produced by additive manufacturing is a very timely and relevant matter, both from a technical and scientific point of view. In the last revision, the reviewer was cordially referred to the comments given by Reviewer #1 and Reviewer #2 explaining this problematic, as well as to a list of illustrative references besides those included in the introduction reflecting the relevance of texture formation in AM Ti alloys. The one reference pointed by the reviewer to argue weak texture of  in AM Ti alloys was also included in this list, since this texture was clearly visible in the pole figures of the pointed work, provided in the previous revision. This is a consequence of epitaxial growth and Burgers OR in AM Ti alloys. As discussed in our previous answer to the reviewer, she/he is comparing the texture between  and  and, while it can be argued that the texture of  is weaker than that of  it must certainly be said that  is still strongly textured. This agrees with the results shown in the mentioned references.

C2. Heat treatments of martensitic Ti alloy can yield impressive ductility, see the work by Charlotte de
Formanoir, e.g. Rejection is recommended.
The reviewer refers to the following work: The pointed investigations reflect again the general problematic of tackling epitaxial growth during AM of Tialloys, as discussed in the previous comment C1 of the reviewer and in the previous revision. Here, we reproduce the pole figures of  and  presented in this work reflecting this effect (it must be mentioned that the pole figure of  was calculated and not measured experimentally): The texture of  and is clearly visible and corresponds to the typical texture observed owing to epitaxial growth and Burgers OR in AM Ti-alloys. In this work, the authors apply subtransus and supertransus postthermal treatments -i.e. below and above the -transus of Ti-6Al-4V to modify this microstructure obtained upon electron beam melting. As pointed in our manuscript (Page 4, lines 7585), and was discussed in the previous revision (comment C3 of Reviewer #1), these strategies correspond to commonly applied treatments to improve the strength-ductility trade-off of as-built AM components, that do not mitigate crystallographic texture and can lead to excessive coarsening, or as the authors of the referred publication . Apart from representing a costly methodology that reduces the economical attractiveness of AM, these posttreatments do not represent an alternative to mitigate crystallographic texture and its effect on mechanical performance of the alloys 1719 ." Therefore, we disagree again with the argumentation of the reviewer, insisting in that texture mitigation in Ti-alloys produced by AM is a very timely and relevant matter.
At last, the authors would like to thank the reviewers for careful revision of the manuscript and the provision of their constructive comments.