李振亮[1]，李扬1,2，李欣1，董瑞1，石玉3，辛海鹰[2]
(1.内蒙古科技大学材料与冶金学院，内蒙古 包头014010；2．中国兵器工业第五二研究所，内蒙古包头 014030；3．包头市特种设备检验所，内蒙古 包头014030)
关键词：TC4钛合金；钨极氩弧焊；退火；显微组织
中图分类号：TG457.19 文献标志码：A
摘要：采用手工钨极氩弧焊焊接不同厚度（25mm/18mm）TC4钛合金板（150mm*150mm），对其分别进行去应力退火（600℃/4h）、等温退火(930℃/2h+530℃/4h)并与未热处理（自然冷却）态进行比较，分析不同热处理工艺对焊缝的组织和力学性能的影响。结果表明，未热处理态焊缝区组织为马氏体，去应力退火后组织为较粗大的针状马氏体，等温退火（930℃/2h+530℃/4h）焊缝根部和顶部组织主要为针状马氏体，中部组织则为马氏体+片状α相，此时焊缝的维氏硬度为434HV。由于等温退火后Al含量降低使合金抗拉强度增大，抗拉强度为904MPa，伸长率为8.0%，拉伸断口在母材区域，属于韧性断裂。
Effect of heat treatment on weldmicrostructure and property of TC4 titanium alloy welding different thicknessplate
LIZhen-liang1, LI Yang1,2, LI Xin1, DONG Rui1, SHI Yu3, XIN Hai-Ying2
(1.Materila and Metallurgy school, InnerMongolia University of Science and Technology, Baotou 014010 China; 2. NO.52institute of china ordnance industries, Baotou 014010, China; 3.Baotouspecial equipment inspection institute, Baotou 014010, China)
Key words:titanium alloy of TC4；TIG welding；isothermalannealing；microstructure
Abstract:The manual argon tungsten-arc welding wasused to weld TC4 titanium alloy plate (150 mm X 150 mm) of different thickness( 25 mm / 18 mm) . The stress relief annealing and isothermal annealing were implemented on the plate , the status of which was compared with that of natural cooling (without heattreatment) sample. The effect of different heat treatment process onmicrostructure and mechanical properties of weld area was analyzed. The resultsshow that microstructure of weld area without heat treatment and the stressrelief annealing are martensite and a rough acicular martensite ,respectively.After isothermal annealing (930℃/2h+530℃/4h), themicrostructure are mainly acicular martensite at root and top of the weld area,with slice martensite + α phase at the central weld area, while the vickershardness of the weld area is 434HV. The tensile strength of alloy was increasedby the lower content of Al element after isothermal annealing. Tensile strengthis 904 MPa , the elongation is 8.0%,and the tensile fracture in the region ofthe base metal belongs to the ductile fracture.