La变质及热处理对Al-7Si-0.44Mg合金组织与硬度的影响  

Effect of La Modification and Heat Treatment on Microstructures and Mechanical Properties of Al-7Si-0.44Mg Alloy

作　　者：屈华[1] 刘海平[1] 刘伟东[1] 

机构地区：[1]辽宁工业大学材料科学与工程学院,辽宁锦州121001

出　　处：《辽宁工业大学学报（自然科学版）》2015年第6期376-379,共4页Journal of Liaoning University of Technology(Natural Science Edition)

基　　金：辽宁工业大学2012教师科研启动基金项目(X201207)

摘　　要：采用实验的方法对Al-7Si-0.44Mg合金进行La变质处理及热处理,分析了时效时间、La变质剂加入量对合金组织及硬度的影响。研究发现:未经La变质处理的Al-7Si-0.44Mg合金宏观组织晶粒较粗大。随着La加入量的增加,合金晶粒明显细化;随着时效时间的延长,共晶硅相和析出相Mg2Si的形貌、大小和分布发生了变化;经La变质后,共晶硅由粗大的长针或片状转变为短杆状或粒状,晶粒明显细化;随着时效时间的延长,Al-7Si-0.44Mg合金发生时效强化,合金硬度增加;La变质剂加入量不同,对Al-7Si-0.44Mg合金的强化效果也不同,当时效温度与时间相同时,La变质剂加入量为0.9%时,对合金的强化效果最好。La modification and heat treatment have an important effect on the actual production of A1-Si-Mg alloy. In the paper, La modification and heat treatment of A1-7Si-0.44Mg alloy was studied through the experimental method and the effect of the amount of La and aging time on hardness and microstructure of alloy were analyzed. The macrostructure of A1-7Si-0.44Mg alloy without La modification is relatively coarse. With the increase of the amount of La, grains size is significantly smaller and its distribution is more uniform. With the increase of aging time, morphology, size and distribution of eutectic silicon phase and precipitate change. When aging time is different, their morphology, size and distribution are also different. La modification makes the shape of euteetic silicon phase change from thick long needle or flake into short rods and its size becomes small. With aging time increasing, the hardness of the alloy increases because of aging strengthening. The amounts of La have different strengthening effect on A1-7Si-0.44Mg alloy, The best strengthening effect occurs with 0.9% La.

关 键 词：AL-SI-MG合金 La变质 组织 硬度 时效 

分 类 号：TG166[金属学及工艺—热处理]