粉末冶金制备镁基复合材料的变形组织及性能

Deformed microstructures and mechanical properties of magnesium matrix composites by powder metallurgy

采用粉末冶金法制备了钛合金颗粒增强镁基复合材料,经过不同挤压比的热挤压变形后,对其显微组织和力学性能进行了检测。结果表明:复合材料的基体晶粒明显小于未增强的镁合金;增强体分布均匀,与基体结合良好,且无界面反应发生;随挤压比的增大,基体晶粒更加细小,复合材料的组织均匀性亦得到提高;超大挤压变形使原镁粉表面的氧化膜得到有效的破碎和分散,从而具有一定的氧化物弥散强化(ODS)作用,进一步提高了复合材料的力学性能。

Ti-6A1-4V particle reinforced magnesium matrix composite was fabricated using powder metallurgy routes. After hot-extruded with different deformation ratios, microstructures and mechanical properties of the composite were investigated by microstructure observation and tensile tests. The results show that, finer grain size, uniform distribution of reinforcements, and good matrix/reinforcement interface bonding were obtained in the composite in addition to the absence of any interracial reaction; the hot-extrusion with an increased deformation ratio may result in a decreased grain size for the matrix, and a better uniformity of microstructures for the composite; the ultrahigh hot-extrusion deformation （ratio of 225：1 ） can efficiently make the oxide layers on the surface of Mg particles break into particulates and disperse in the matrix, thereby further increasing the mechanical properties of magnesium matrix composites due to the oxide dispersion strengthening （ODS） effect of the MgO particulates.