激光增材制造高性能大型钛合金构件凝固晶粒形态及显微组织控制研究进展  

Progress on Solidification Grain Morphology and Microstructure Control of Laser Additively Manufactured Large Titanium Components

作　　者：王华明[1] 张述泉[1] 王韬[1] 朱言言 WANG Huaming;ZHANG Shuquan;WANG Tao;ZHU Yanyan(National Engineering Laboratory of Additive Manufacturing for Large Metallic Components,Beihang University,Beijing 100191China)

机构地区：[1]北京航空航天大学大型金属构件增材制造技术国家工程实验室,北京100191

出　　处：《西华大学学报（自然科学版）》2018年第4期9-14,共6页Journal of Xihua University:Natural Science Edition

基　　金：国家重点研发计划(2016YFB1100400);博士后科学基金(2017M620014)

摘　　要：简要介绍高性能大型关键金属构件激光增材制造的技术特点,总结本团队在高性能大型关键钛合金构件激光增材制造过程中,对凝固晶粒形态和显微组织控制的主要研究进展:发现了钛合金构件激光增材制造过程中熔池底部外延生长和顶部异质形核两种主要形核生长机制,建立了基于增材制造工艺参数及凝固条件控制的全柱状晶、全等轴晶和柱状晶-等轴晶混合组织等凝固晶粒形态主动控制技术;发现了激光增材制造双相钛合金构件高性能特种双态显微组织新形态,并建立其固态相变理论及显微组织主动控制技术。The technological advantages of laser additive manufacturing （LAM） for high performance large critical metallic components are briefly introduced, and the main progresson control of solidification grain morphologiesand post-LAM heat- treatment microstructuresfor the LAMed large critical titanium components in the author’s team issummarized.The epitaxial growth from the pool-bottom for columnar grain formation and surface heterogeneous nucleation for equiaxed grain formation are found to be the two dominant solidification mechanisms during the layerwiselaser additive manufacturing process. A completed set of solidification grain morphology control method was established and LAMedlarge titanium components with full columnar grains, full equiaxed grains and columnar/equiaxed mixed grains were produced by active controlling the solidification conditions during LAM process. A new special bi-modal microstructure was discovered during the post-LAM heat treatment process and its solid-state phase transformation theory is established.

关 键 词：激光增材制造 钛合金 凝固晶粒形态 显微组织 热处理 

分 类 号：TG665[金属学及工艺—金属切削加工及机床]