摘要
采用激光熔化沉积技术直接成形TC17钛合金构件,利用OM、SEM以及XRD分析其显微组织特征,并重点研究了其在激光短时循环加热冷却作用下的固态相变行为及显微组织演化特点。结果表明,激光熔化沉积TC17钛合金具有定向外延生长的＂指节＂状晶粒和少量等轴晶交替排列的凝固组织,其显微组织是由不规则片状初生α相和细小网篮状β转变组织组成的超细特殊双态组织。最后约12个沉积层内由于热循环历史不同,使得不同沉积层固态相变显微组织不同：顶部4个沉积层内显微组织为相变点以上快速冷却形成的细针状马氏体,第N-4~N-6层由细针状马氏体和马氏体分解形成的少量不规则片状初生α相组成,第N-7~N-11层内逐渐形成特殊双态组织。
Microstructure characteristics of the laser melting deposited TC17 titanium alloy components were analyzed by OM, SEM and XRD. The solid-state phase transformation and the microstructure evolution under the effect of laser short term cycle of heating and cooling were researched. Results show that the laser melting deposited TC17 titanium alloy consists of directionally solidified ＂knuckle＂ grains and a few equiaxed grains, which are arranged alternately. The microstructure of the laser melting deposited TC17 titanium alloy is fine duplex microstructure composed of irregular primary lamellar α and basketwave transformed β. Solid-phase transformation is shown in the last twelve depositing layers： the microstructure in the last four layers is Martensite; in the 5th to 7th layer is mainly acicular α and a little irregular coarse α; in the 8th to 12th layer is coarser and shorter α with underdeveloped serrated interface and the second α is fine basketwave microstructure.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2013年第4期724-729,共6页
Rare Metal Materials and Engineering
基金
国家"973"计划资助项目(2011CB606305)
