摘要
研究了形变AZ91镁合金的相结构和精细组织及其对SIMA法半固态组织形成的影响。结果表明,形变AZ91镁合金组织由细小的αMg等轴晶和Mg17Al12化合物颗粒组成。在αMg基体中存在着大量的大角度亚晶和较高密度的位错缠结以及较大程度的晶格畸变。Mg17Al12相颗粒、高密度位错区及具有高畸变能的晶界为半固态合金提供了应变诱发激活液化源,而晶界、亚晶界则为半固态温度下溶质原子的扩散及液相的浸渗提供了便捷的通道,加速了半固态合金的液化和粒化进程。加热温度为565℃、等温时间5min时,即可获得晶粒形态圆整、分布均匀、固相率为57%的半固态合金。
The phase structure,microstructure of deformed AZ91 Mg alloy and their effects on the formation of semi-solid microstructure in SIMA were investigated.Deformed AZ91 Mg is composed of fine equaixed α-Mg phase and Mg_(12)Al_(17) phase.There exist a great mount of sub-crystal with big angle and dislocation tangles with high density as well as lattice distortion in α-Mg matrix.Mg_(12)Al_(17) phase,dislocation with high density as well as grain boundary with high distortion energy can be responsible for stress induced melting of semi-solid alloy,and the solute diffusion and liquid infiltration are dependent on the grain boundary and sub-grain boundary,which accelerate the melting and granularization of the semi-solid alloy.The semi-solid AZ91 Mg alloy with uniform distribution and spheroidal grain as well as 57% solid fraction can be obtained with heating temperature at 565℃ for holding time of 5min.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2005年第6期354-357,共4页
Special Casting & Nonferrous Alloys
基金
陕西省教育厅产业化培育项目(02JC33)
西安市科技局科学技术计划项目(GG200247)
关键词
形变镁合金
位错
半固态
激活液化
Deformed Mg Alloy,Dislocation,Semi-solid,Activation Melting
