Microstructure control in additive manufacturing of metals and ceramics

Martensite in Ti-6Al-4V is known to decompose under heating. This study employs rapid laser heating in situ in a synchrotron to study changes in the diffraction profiles during the martensite decomposition process.

Additive manufacturing is known to create microstructures that cannot be achieved by conventional alloy processing. Here, heat treatment of an additively-manufactured aluminum alloy creates a hierarchical microstructure with a large number of precipitates, achieving high strength and ductility.

Refractory high-entropy alloys are attractive for high-temperature applications, but are challenging to process. Here, a method is shown for identifying a processing window that allows the additive manufacturing of a TiZrNbTa refractory alloy with a low defect content and mechanical properties comparable to as-cast samples.

In-situ x-ray studies have proven to be vital in understanding solidification behavior during additive manufacturing of alloys. Here, operando synchrotron diffraction of a superalloy reveals the effects of solidification dynamics on dendrite deformation mechanisms during laser melting.

Understanding the effects of changing process parameters during additive manufacturing is vital for building high-quality parts. Here, operando tomographic microscopy during laser-based processing of alumina reveals detailed insight into process dynamics, including melt pool behavior and defect formation.

Additive manufacturing typically uses spherical powder feedstock prepared by gas or plasma atomization. Here, a high-performance aluminum alloy is prepared from cold mechanically derived powder, showing the viability of non-spherical powders for good mechanical properties.

Beam oscillation is an attractive method to achieve melt pool and microstructure control in laser powder bed additive manufacturing. Here, in-situ X-ray imaging and high-fidelity modeling reveal the unique keyhole dynamics in a kHz laser oscillation mode.