共晶组织对2E12铝合金热变形行为及组织演变的影响  

Effect of eutectics on hot deformation behaviors and microstructure evolutions of 2E12 aluminum alloy

作　　者：陈宇强[1,2] 宋文炜[1] 潘素平 刘文辉[1,2] 唐昌平[1,2] 

机构地区：[1]湖南科技大学高温耐磨材料及制备技术湖南省国防技术重点实验室,湖南湘潭411201 [2]湖南科技大学难加工材料高效精密加工湖南省重点实验室,湖南湘潭411201 [3]中南大学高等研究中心,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2017年第11期2950-2959,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51405153;51475162)~~

摘　　要：采用不同热处理方法制备过饱和固溶体(1号合金)和富含共晶组织(2号合金)这2种具有典型组织特征的2E12合金。结合热模拟实验和显微组织观察,针对2种合金铸锭在变形温度为340~490℃、应变速率为0.001~10 s-1下的变形行为以及组织演变特征进行研究。研究结果表明:在0.001~0.1 s-1的应变速率下,2号合金具有较高的峰值应力;在10 s-1的应变速率下,1号合金具有较高的峰值应力;1号合金在热变形过程中的主要失效形式表现为三叉晶界的失稳开裂;2号合金在340℃/10 s-1变形时的主要失效形式为晶界共晶组织的碎化;在490℃/0.001 s-1变形时的主要失效形式为晶界共晶组织的熔化开裂;在相同变形条件下,1号合金更容易发生动态再结晶且晶粒更细小;弥散分布的T相粒子可以促进合金均匀变形并且细化晶粒。Two kinds of alloys whose microstructures were featured with supersaturated solid solution （alloy 1） andenriched with eutectics （alloy 2） were prepared by different heat-treatment methods, respectively. By combiningisothermal hot compression test with microstructure observation, the hot deformation behaviors and microstructureevolution of both alloys were studied at temperature range of 340-490 ℃ and strain rate range of 0.001？10 s-1. Theresults show that alloy 2 possesses a higher peak-stress value deformed at 0.001-0.1 s-1, while alloy 1 possesses a higherpeak-stress value deformed at 10 s-1. The main failure mode of alloy 1 is cracking at triple grain boundaries （GBs）. Whendeformed at 340 ℃/10 s-1, the main failure modes of alloy 2 is the fracture of eutectics at GBs. When deformed at490 ℃ /0.001 s-1, the main failure modes of alloy 2 is the cracking caused by eutectic melting. The dynamicrecrystallization takes place easier in alloy 1 and thus makes a smaller grain size. The dispersively distributed T-phaseparticles promote the homogeneous deformation of alloy and also refine grain size.

关 键 词：2E12铝合金 热变形 共晶组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]