CAJ | 학술논문

利用传统拉伸试验机和霍普金森(Hopkinson)拉杆实验装置研究电子束焊接的Ti-6Al-4V合金在应变率为10-3和103 s-1时的准静态和动态拉伸行为,利用光学显微镜和扫描电子显微镜观察基体材料和焊缝材料的微观组织,研究基体材料和焊接材料在拉伸实验后的断裂特征.结果表明:在应变率分别为10-3和103 s-1的条件下,焊缝材料的强度明显高于基体材料,焊缝材料的伸长率低于基体材料.同时,焊缝材料和基体材料均为应变率敏感材料;当应变率从10-3上升到103 s-1时,焊缝材料的伸长率明显提高,而基体材料的伸长率基本没有变化;焊缝材料的断裂模式由脆性断裂转向韧性断裂,造成从准静态加载条件到动态加载条件下焊缝材料伸长率的提高.
이용전통랍신시험궤화곽보금삼(Hopkinson)랍간실험장치연구전자속한접적Ti-6Al-4V합금재응변솔위10-3화103 s-1시적준정태화동태랍신행위,이용광학현미경화소묘전자현미경관찰기체재료화한봉재료적미관조직,연구기체재료화한접재료재랍신실험후적단렬특정.결과표명:재응변솔분별위10-3화103 s-1적조건하,한봉재료적강도명현고우기체재료,한봉재료적신장솔저우기체재료.동시,한봉재료화기체재료균위응변솔민감재료;당응변솔종10-3상승도103 s-1시,한봉재료적신장솔명현제고,이기체재료적신장솔기본몰유변화;한봉재료적단렬모식유취성단렬전향인성단렬,조성종준정태가재조건도동태가재조건하한봉재료신장솔적제고.
The quasi-static and dynamic tensile behaviors in electron beam welded (EBW) Ti-6Al-4V alloy were investigated at strain rates of 10-3 and 103 s-1, respectively, by materials test system (MTS) and reconstructive Hopkinson bars apparatus. The microstructures of the base metal (BM) and the welded metal (WM) were observed with optical microscope. The fracture characteristics of the BM and WM were characterized with scanning electronic microscope. In Ti-6Al-4V alloy joint, the flow stress of WM is higher than that of BM, while the fracture strain of WM is less than that of BM at strain rates of 103 and 10-3 s-1, respectively. The fracture strain of WM has apparent improvement when the strain rate rises from 10-3 to 103 s-1, while the fracture strain of BM almost has no change. At the same time, the fracture mode of WM alters from brittle to ductile fracture, which causes improvement of the fracture strain of WM.