Microstructural homogeneity and mechanical behavior of a selective laser melted Ti-35Nb alloy produced from an elemental powder mixture  

作　　者：Jincheng Wang Yujing Liu Chirag Dhirajlal Rabadia Shun-Xing Liang Timothy Barry Sercombe Lai-Chang Zhang 

机构地区：[1]School of Engineering,Edith Cowan University,270Joondalup Drive,Joondalup,Perth,WA 6027,Australia [2]School of Engineering,M050,The University of Western Australia,35 Stirling Highway,Crawley,Perth,WA 6009,Australia

出　　处：《Journal of Materials Science & Technology》2021年第2期221-233,共13页材料科学技术（英文版）

基　　金：support of the ECU Postgraduate Research Award;Forrest Research Foundation Ph D Scholarship;the Australian Government Research Training Program Scholarship(ECU);the facilities,and the scientific and technical assistance of the Australian Microscopy&Microanalysis Research Facility at the Centre for Microscopy,Characterisation&Analysis,The University of Western Australia,a facility funded by the University,State and Commonwealth Governments。

摘　　要：Although using elemental powder mixtures may provide broad alloy selection at low cost for selective laser melting(SLM), there is still a concern on the resultant microstructural and chemical homogeneity of the produced parts. Hence, this work investigates the microstructure and mechanical properties of a SLM-produced Ti-35 Nb composite(in wt%) using elemental powder. The microstructural characteristics including ? phase, undissolved Nb particles and chemical homogeneity were detailed investigated.Nanoindentation revealed the presence of relatively soft undissolved Nb particles and weak interface bonding around Nb-rich regions in as-SLMed samples. Solid-solution treatment can not only improve chemical homogeneity but also enhance bonding through grain boundary strengthening, resulting in43 % increase in tensile elongation for the heat-treated Ti-35 Nb compared to the as-SLMed counterpart. The analyses of tensile fractures and shear bands further confirmed the correlation between the different phases and the ductility of Ti-35 Nb. In particular, the weak bonding between undissolved Nb and the matrix in the as-SLMed sample reduces its ductility while the ? grains in solid-solution treated Ti-Nb alloy can induce a relatively stable plastic flow therefore better ductility. This work sheds insight into the understanding of homogenization of microstructure and phases of SLM-produced alloys from an elemental powder mixture.

关 键 词：Titanium-niobium Selective laser melting Microstructure NANOINDENTATION Mechanical behavior 

分 类 号：TG146.23[一般工业技术—材料科学与工程] TG665[金属学及工艺—金属材料]