Mg-Zn-Gd镁合金SSIMA法等温半固态组织演变  

Semi-Solid Microstructural Evolution of Mg-Zn-Gd Magnesium Alloy by the SSIMA Process

作　　者：范俊凯 杨光昱[1] 轩敏鑫 刘少军[1] 介万奇[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室 [2]新乡市航空锻铸有限公司

出　　处：《特种铸造及有色合金》2014年第8期816-820,共5页Special Casting & Nonferrous Alloys

基　　金：国家自然科学基金资助项目(51071129;51227001);国家重点基础研究发展计划(973计划)资助项目(2011CB610400)

摘　　要：研究了Mg-5.5Zn-2Gd-0.6Zr镁合金在不同挤压下的SSIMA法等温半固态组织演变过程和组织粗化行为。结果表明,在相同挤压比条件下,α-Mg平均晶粒直径与等温时间之间的关系为:等温处理后平均晶粒直径的三次方与初始平均晶粒直径的三次方的差值等于粗化速率常数与等温时间的乘积。粗化速率常数K随挤压比的增大而减小。当挤压比分别为10、15、30时,镁合金横向组织晶粒粗化速率常数K分别为359、289、266μm3/s。另外,挤压比越高,镁合金半固态组织等温转变各阶段的进程加快,α晶粒的圆整度和均匀程度越好。Semi-solid microstructural evolution of extruded Mg-5.5Zn-2Gd-0.6Zr magnesium alloy with different extrusion ratio by the SSIMA process was investigated. It is found that the relationship be tween the average diameter of a-Mg grains and the isothermal holding time meets the difference between the cube of average grain diameter and initial average grain diameter equal to the coarstning constant K and the isothrmal time t under the condition of the same extrusion ratio. The coarsening rate constant K is decreased with the increase of the extrusion ratio, which reaches 359 μm3/s,289 μm3/s and 266 μm3/ s when the extrusion ratio is 10, 15 and 30, respectively. It is also found that the semi-solid isothermal evolution process of the experimental alloy is accelerated with the increase of the extrusion ratio, mean while, the roundness and uniformity of a-Mg grains also are improved.

关 键 词：挤压镁合金 简化SIMA法工艺 半固态成形 粗化 微观组织 

分 类 号：TG292[金属学及工艺—铸造]