【摘要】 用放电等离子烧结法（SPS）制备了不同增强相的MoSi₂基复合材料,系统研究了第二相对MoSi₂基复合材料组织与性能的影响,探讨了MoSi₂基复合材料的断裂方式及增韧机制。结果表明:第二相颗粒的加入均能不同程度地提高MoSi₂的强韧性;ZrO₂对提高断裂韧性最有效,其中20%ZrO₂/MoSi₂材料达到6.8 Mpam^1/2,比纯MoSi₂提高了95.4%,表现为微裂纹增韧和弥散强化;β-Si₃N₄对提高显微硬度、抗压强度最有效,其中20%β-Si₃N₄/MoSi₂分别达到16.01Gpa与2260Mpa,比纯MoSi₂提高了31.7%与119.4%,表现为细晶强化;同时加入ZrO₂与β-Si₃N₄能起到相变增韧和细晶强化的协同作用,表现出最佳的强韧性能,其中,10%ZrO₂/20%β-Si₃N₄/MoSi₂的维氏硬度、抗压强度、断裂韧性分别比MoSi₂提高了24.7%、104.3%、90%。更多还原

【Abstract】 MoSi₂ matrix composites with different strengthen phases were prepared by the spark plasma sintering （SPS） technique,the influence of second phase on the microstructure and mechanical properties of MoSi₂ matrix composites were systematically studied,and the fracture mechanics and toughening mechanism of MoSi₂ matrix composites also be investigated.The results show that compared with MoSi₂ monomer,the hardness,compression strength,fracture toughness of 10%ZrO₂/20%,β-Si₃N₄/MoSi₂ composite increase by 24.7%,104.3%,90%respectively;Furthermore,dispersion strengthening and microcrack toughening are the major toughening mechanism of ZrO₂/MoSi₂ composite,fine-grained strengthening is the toughening mechanism of,β-Si₃N₄/MoSi₂ composite,and the ZrO₂/β-Si₃N₄/MoSi₂ composite is the effect of transformation toughening and fine-grained strengthening.更多还原