Effects of heat treatments on microstructure and properties of Ti-6Al-4V ELI alloy fabricated by electron beam melting (EBM)

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• 作者：Haize Galarraga^a ; Robert J. Warren ; ^a ; ^{rwarren@wpi.edu} ; Diana A. Lados^a ; Ryan R. Dehoff^b ; ^c ; Michael M. Kirka^b ; ^c ; Peeyush Nandwana^b ; ^c
• 关键词：Additive manufacturing ; Electron beam melting ; Ti-6Al-4V ; Microstructure evolution ; Mechanical characterization ; Heat treatment
• 刊名：Materials Science and Engineering: A
• 出版年：2017
• 出版时间：8 February 2017
• 年：2017
• 卷：685
• 期：Complete
• 页码：417-428
• 全文大小：4484 K
• 卷排序：685

文摘

Electron beam melting (EBM) is a metal powder bed fusion additive manufacturing (AM) technology that is used to fabricate three-dimensional near-net-shaped parts directly from computer models. Ti-6Al-4V is the most widely used and studied alloy for this technology and is the focus of this work in its ELI (Extra Low Interstitial) variation. Microstructure evolution and its influence on the mechanical properties of the alloy in the as-fabricated condition have been documented by various researchers. In the present work, different heat treatments were performed based on three approaches in order to study the effects of heat treatments on the unique microstructure formed during the EBM fabrication process. In the first approach, the effect of various cooling rates after the solutionizing process was studied. In the second approach, a correlation between the variation of α lath thickness during aging and the subsequent effect on mechanical properties was established. Lastly, several combined solutionizing and aging experiments were conducted; the results will be systematically discussed in the context of structural performance and design.