原位自生Al_2O_3-TiC/Al复合材料高温压缩变形行为的研究

Study of Deformation Behaviors of Compression of In-situ Al_2O_3-TiC/Al Composites Fabricated by Melting Cast Method at Elevated Temperature

利用熔铸技术制备了原位自生Al2O3-TiC/Al复合材料。借助SEM、TEM和高温材料实验机等,对工业纯铝和Al2O3-TiC/Al复合材料的高温变形行为进行较为深入的探讨。结果表明,实验材料的流变应力随压缩变形温度的升高而下降,高的应变速率将提高流变应力的整体水平;工业纯铝在523~723K、Al2O3-TiC/Al复合材料在523K-623K温度区间的压缩变形以晶内位错运动为主要特征;在623~723K温度区间,Al2O3-TiC/Al复合材料的压缩变形以晶内位错运动以及晶界的滑移为主要特征。

The in-situ Al2O3-TiC/Al composites were fabricated by melting cast method.By means of SEM,TEM and a tensile test machine and so on,the mechanisms and deformation behaviors of the industrially pure Aluminum and Al2O3-TiC/Al composites were deeply investigated.The results showed that the flow stresses decreased with temperature increasing,and high strain rates raised the whole levels of deformation curves of both materials.The mechanisms of compressive deformation of industrially pure aluminum ranged from 523K to 723K and the composites ranged from 523K to 623K were characterized by the movement of dislocations in the grains;the mechanisms of compressive deformation of the composites ranged from 623K to 723K were characteristic of the movement of dislocations in the grains and creeping of grain boundaries.