【摘要】：分別向AZ81鎂合金熔液中加入0.5%,1.0%,1.5%(質(zhì)量分?jǐn)?shù))的Pb,壓鑄成型并進(jìn)行時(shí)效熱處理,然后對(duì)其微觀組織和180℃拉伸性能進(jìn)行了研究。結(jié)果顯示:Pb對(duì)壓鑄態(tài)AZ81的微觀組織有一定的晶粒細(xì)化作用,且隨著Pb加入量的增加,晶粒細(xì)化作用有一定的增加趨勢(shì);Pb主要以固溶形式存在于壓鑄態(tài)AZ81鎂合金的α-Mg基體和β-Mg17Al12相中;時(shí)效后,Pb在壓鑄AZ81鎂合金中依然主要以固溶形式存在,在α-Mg晶內(nèi)和晶界上均有Mg17Al12相析出,Pb可在一定程度上抑制晶界上的不連續(xù)析出并促進(jìn)晶內(nèi)連續(xù)析出;180℃拉伸結(jié)果顯示,隨著Pb加入量的增多,各成分未時(shí)效試樣的抗拉強(qiáng)度變化幅度不大,含Pb時(shí)效態(tài)試樣中溫抗拉強(qiáng)度隨Pb含量增加呈上升趨勢(shì),最高平均強(qiáng)度為181 MPa,含Pb試樣時(shí)效態(tài)抗拉強(qiáng)度比同成分未時(shí)效態(tài)均有所提高;各試樣時(shí)效態(tài)屈服強(qiáng)度均比未時(shí)效態(tài)高;Pb元素和時(shí)效熱處理均使壓鑄AZ81鎂合金延伸率下降;時(shí)效使AZ81鎂合金傾向于脆性斷裂,塑性下降。
[Abstract]:The microstructures and tensile properties of AZ81 magnesium alloys were studied by adding 0.5 and 1.0% (mass fraction) Pb, die-casting and aging heat treatment respectively to the molten solution of AZ81 magnesium alloys. The results show that Pb has a certain grain refinement effect on the microstructure of die-cast AZ81, and with the increase of Pb content, the grain refinement has a certain increasing trend. Pb mainly exists in 偽-Mg matrix and 尾-Mg17Al12 phase of die-cast AZ81 magnesium alloy in the form of solid solution. After aging, Pb still exists in the form of solid solution in die-cast AZ81 magnesium alloy, and there is Mg17Al12 phase precipitation in 偽-Mg crystal and grain boundary. Pb can restrain discontinuous precipitation at grain boundary to some extent and promote continuous precipitation within grain boundary. The tensile results at 180 鈩，

本文編號(hào)：2420833