Fine equiaxed β grains and superior tensile property in Ti–6Al–4V alloy deposited by coaxial electron beam wire feeding additive manufacturing

• DOI: 10.1007/s40195-020-01073-5
• Publication Date: 2020-06-05T06:03:06Z
• Authors: Jiahua Zhang; Yi Yang; Sheng Cao; Zhiqiang Cao; Dmytro Kovalchuk; Songquan Wu; Enquan Liang; Xi Zhang; Wei Chen; Fan Wu; Aijun Huang
• Keywords: 0203 mechanical engineering; 02 engineering and technology

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.