Coarse columnar β grains result in anisotropic mechanical properties in Ti alloys deposited by additive manufacturing. This study reports that Ti–6Al–4V alloy fabricated by coaxial electron beam wire feeding additive manufacturing presents a weak anisotropy, high strength and ductility. The superior tensile property arises from a microstructure with fine equiaxed β grains (EGβ), discontinuous grain boundary α phase and short intragranular α lamellae. A large region of fine EGβ arises from a special combination of the temperature gradient and solidification rate, and attractive α morphology is caused by solid phase transformations during interpass thermal cycling and post heat treatments.

中文翻译：

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同轴电子束送丝增材制造沉积的Ti-6Al-4V合金中的细等轴β晶粒和优异的拉伸性能

粗大的柱状β晶粒会导致通过增材制造沉积的Ti合金的各向异性力学性能。这项研究报告说，通过同轴电子束送丝添加剂制造工艺制造的Ti-6Al-4V合金具有较弱的各向异性，高强度和延展性。优异的拉伸性能来自具有细等轴β晶粒（EGβ），不连续晶界α相和短晶粒内α晶层的组织。温度梯度和凝固速率的特殊结合产生了大面积的精细EGβ，而有吸引力的α形貌是由道间热循环和后热处理过程中的固相转变引起的。