Mg-3Al合金中Mn对碳化铝异质形核的影响机制  

Influencing Mechanism of Manganese on Heterogeneous Nucleation of Aluminum Carbide in Mg-3% Al alloy

作　　者：詹美清[1] 李克[1] 王飞[1] 廖建南 吴尚敏[1] 周耐根[1] 

机构地区：[1]南昌大学,江西南昌330031

出　　处：《稀有金属材料与工程》2016年第3期644-649,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51264032);江西省自然科学基金(20114BAB206037);教育部留学回国人员科研启动基金(第44批)

摘　　要：采用光学显微镜、扫描电镜、EDS能谱和差热分析研究了Mg-3Al合金中AlMn中间相的形貌特征,以及Mn含量对碳质变质剂异质形核作用的影响机制。结果表明:加碳变质处理产生的碳化铝可成为a-Mg的有效形核核心;当合金中的Mn含量小于0.32%(质量分数)时,加碳变质处理能使a-Mg晶粒明显细化,最小平均晶粒尺寸达到66μm,此时形成大量细小的球状和杆状Al Mn中间相,有助于晶粒细化;但当Mn含量增加到0.56%时,形成更多粗大的十字花瓣状AlMn中间相。过量的溶质Mn易与A1_4C_3粒子结合形成不利于形核的Al-Mn-C-O复杂化合物,并导致a-Mg晶粒粗化。The morphological characteristics of AlM n intermetallics in Mg-3Al alloys and the influencing mechanism of manganese on heterogeneous nucleation of aluminum carbide（Al4C3）were studied by OM,SEM,EDS and DTA.Results show that Al4C3 particles are produced by carbon inoculation and then they act as the potent heterogeneous nuclei for primary Mg.The a-Mg grain can be greatly refined with carbon inoculation when the content of Mn is below 0.32 wt%.The minimum average grain size of 66 μm can be obtained due to the formation of numerous small ball-like and short rod-like AlM n intermetallics,which is helpful to grain refinement.In contrast,coarser cross petals-like AlM n intermetallics are formed when the content of Mn is increased to 0.56 wt%.Therefore,the Al4C3 particles are easily poisoned by excess Mn solute and turn to be complex Al-Mn-C-O compounds,which are not effective heterogeneous nuclei of primary Mg,hence leading to the coarsening of a-Mg grain.

关 键 词：镁合金 MN 碳化铝 异质形核 AlMn中间相 

分 类 号：TG146.22[一般工业技术—材料科学与工程] TB31[金属学及工艺—金属材料]