钛合金颗粒增强镁基复合材料的制备与性能

Fabrication and Properties of Ti-6Al-4V Particles Reinforced Magnesium Matrix Composite by Powder Metallurgy

采用粉末冶金法制备了20%Ti-6Al-4V颗粒增强MB15镁基复合材料的试样。按照阿基米得法检测了不同状态试样的密度,借助光镜和扫描电镜探索了挤压棒变形和组织的特点,并结合室温拉伸试验研究了热挤压变形对试样组织及力学性能的影响规律。结果表明:烧结态的密度较低,而热挤后的密度已接近理论值;挤压棒的变形和组织都不均匀;二次挤压可以进一步细化晶粒、提高复合材料的力学性能;Ti-6Al-4V颗粒可以用来强化镁合金,且其增强效果明显好于SiC陶瓷颗粒。

Samples of 20wt.%Ti-6Al-4V particles reinforced MB15 magnesium matrix composite were fabricated by powder metallurgy route. Densities of sin tered and extruded samples were measured using Archimedes＇ principle. Deformation and microstructure of extruded bars were investigated with optical microscope and scan electric microscope （SEM）. Effect of hot-extrusion on microstructure and mechanical properties were studied by microstructure observation and tensile tests. The results show that the lower density, of sintered sample is increased by hot-extrusion approximately near theoretical density of the composite; and both of deformation and mierostructure were uneven in the outer layer and the center of hot-extruded bars; moreover, the second extrusion could further decrease the matrix grain size and increase the mechanical properties when compared with the first extrusion. Therefore, Ti-6Al-4V particles cart be used to strengthen Mg and Mg aLloys, and its reinforcing erect may be more superior to thai of SiC particles.