(合肥工业大学 材料科学与工程学院,合肥 230009)
摘 要: 采用高压扭转工艺将SiC和Al的混合粉末直接制备金属基复合材料。用金相显微镜、显微维氏硬度计、万能试验机和扫描电镜分析压力对SiCp-Al复合材料的显微组织和力学性能的影响。结果表明:压力越高,对SiCp-Al复合材料粉末成形的应变积累越有利;压力越高,扭转前粉末的致密程度越高,对SiCp-Al复合材料粉末成形的应变积累越有利,SiC颗粒在Al基体内的分布越均匀,显微硬度有所提高,但增幅不大;当压力从0.5 GPa增大至0.62 GPa,材料的屈服强度增加32.6%,但抗拉强度和伸长率均分别减小4%和25.5%。拉伸断口以大小不一的脱粘韧窝为主要特征。
关键字: SiCp-Al复合材料;高压扭转;显微组织;力学性能
(School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China)
Abstract:SiC particles and Al powder mixtures (SiCp-Al composites) were successfully fabricated into the metal matrix composites by high-pressure torsion (HPT). The effects of pressure on the microstructure and mechanical properties of the composites were investigated by optical telescope, microhardness-testing device, universal testing machine and scanning electronic telescope. The results show that higher pressure is more helpful to the strain accumulation during the power forming of SiCp-Al composites. In the HPT process, the higher the pressure is, the better the powerful densification is, the higher the accumulated strain is, and the more homogeneous of the SiC particles are, while the increase of microhardness is not so high. When the pressure increases from 0.5 GPa to 0.62 GPa, the yield strength increases by 32.6%, while the tensile strength and elongation decrease by 4% and 25.5%, respectively. The fracture surface of the dimples shows various sizes as the main feature.
Key words: SiCp-Al composites; high-pressure torsion; microstructure; mechanical property