AZ31B镁合金TIG焊接头的热碾压力学改性实验研究  

Experimental Research on Hot Rolling to Improve TIG Welding Joint Mechanical Properties for AZ31B Magnesium Alloy

作　　者：李晓泉[1] 初雅杰[1] 杨宗辉[1] 

机构地区：[1]南京工程学院材料工程学院,南京211167

出　　处：《航空材料学报》2012年第3期46-50,共5页Journal of Aeronautical Materials

基　　金：国家自然科学基金资助项目(51075197);江苏省自然科学基金资助项目(BK2009354);江苏省高校"青蓝工程"中青年学术带头人培养对象资助项目;南京工程学院科研项目(CKJ2009002)

摘　　要：为探索镁合金焊接接头的力学性能改性方法,以母材金属同材质丝材为填充材料,对AZ31B板材进行TIG对接焊,然后在高温拉伸试验机上将对接取样用专门制作的陶瓷电加热装置加热至350℃进行接头区域热碾压试验。将焊态及经热碾压的对接焊取样加工成拉伸试样测试其常温力学性能,同时对焊接接头进行金相分析,借助扫描电镜及其附带能谱仪对拉伸断口作微观形貌和微区成分分析。结果表明,经热碾压后,TIG焊接头的抗拉强度可达到母材金属的90%,伸长率也有明显的改善;热碾压可有效改变β-Mg17Al12析出相在焊缝α-Mg基体组织晶界的连续网状分布态,使其重新固溶后在晶内以弥散质点态析出进而造成弥散强化效应;同时热碾压又能促使铸态焊缝发生动态再结晶从而使微观组织得以重构及细化。To explore method of improving mechanical properties for magnesium alloy welding joint, TIG welding was applied to butt AZ31B magnesium alloy plates with the same composition filled wire, specimens cut from test piece of butt welding were heated up to 350℃ by a special ceramic electric heater, then experiments have been carried out on high temperature tensile machine. Specimens with as-welded and hot rolled were machined as tensile speeimens to test normal atmospheric temperature mechanical properties. Mean- while welding joint was analyzed using optical metallographic microscope and fracture morphology as well as micro-area chemical com- position were researched with the help of scanning electronic microscopy and energy spectrum analyzer appended. The results show that applying hot rolling procedure, the tensile strength of TIG welding joint can be increased up to 90% of that of the base metal and elon- gation rate also improved obviously. Hot rolling may effectively change network-like distribution of 13-Mg17 All2 precipitate on α-Mg grain boundary of weld mierostrueture and make it solid solve to re-precipitate in way of dispersoidpartiele in grain, resulting in disper- sion-strengthening effect. In addition, hot rolling may also promote as-cast weld mierostrueture to produce dynamic re-crystallization and make microstructure reconstructed and refined.

关 键 词：镁合金 焊接接头 热碾压 力学性能 弥散强化 

分 类 号：TG403[金属学及工艺—焊接]