(1. 重慶大學 材料科學與工程學院，重慶 400045；
2. 重慶大學 國家鎂合金材料工程技術(shù)研究中心，重慶 400044)
摘 要: 研究均勻化、擠壓以及熱處理對Mg-5.77%Zn-0.94%Mn(ZM61)(質(zhì)量分數(shù))鎂合金顯微組織和力學性能的影響。結(jié)果表明：ZM61鑄態(tài)組織呈枝晶結(jié)構(gòu)，枝晶間網(wǎng)狀的和枝晶內(nèi)顆粒狀的金屬間化合物為Mg7Zn3；經(jīng)(330 ℃，8 h)+(420 ℃，2 h)的兩級均勻化處理后，化合物絕大部分溶解于基體；兩級均勻化處理可大幅降低合金的擠壓溫度(降低幅度30 ℃)、減少擠壓態(tài)組織中的殘余流線、提高擠壓態(tài)合金的伸長率、縮短固溶時間，但并未明顯細化擠壓態(tài)合金的晶粒；對于可時效強化的ZM61變形鎂合金來說，晶粒大小對其力學性能的影響不大，起主要強化作用的是時效析出相的類型、尺寸和彌散程度；ZM61在時效過程中主要析出沿[0001]α-Mg的 桿狀相和平行于(0001)α-Mg的 盤狀相的析出相，其中 桿狀相為起主要強化作用的析出相。
關(guān)鍵字: Mg-5.77%Zn-0.94%Mn(ZM61)合金；均勻化；擠壓；固溶處理；時效；析出相
（1. College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China）
Abstract:The effects of homogenization, extrusion and heat treatment on microstructure and mechanical properties of Mg-5.77%Zn-0.94%Mn (ZM61) (mass fraction) Mg alloy were investigated. The results show that the microstructure of the as-cast ZM61 alloy is typical dendrite structure, the interdendritic network intermetallic compounds are Mg7Zn3. The majority of these compounds dissolves into the matrix after (330 ℃, 8 h)+(420 ℃, 2 h) homogenization treatment. Two-step homogenization can significantly decrease the extrusion temperature (decreased by 30 ℃), reduce the residual streamline in microstructure, improve the elongation of as-extruded alloy, and shorten the solution time, but not significantly refine the grain size of the as-extruded alloy. For wrought ZM61 Mg alloy, the precipitates type, size and dispersion degree play the major role in strengthening, the effect of grain size is weak. There are mainly two types of precipitates in as-aged alloy, one is rod-shaped phase along [0001]α-Mg, the other is plate-shaped phase parallel to (0001)α-Mg, and the rod-shaped phase is primarily strengthening precipitates.
Key words: Mg-5.77%Zn-0.94%Mn(ZM61) alloy; homogenization; extrusion; solution treatment; aging; precipitates
