SPS烧结工艺对TiC/6061Al复合材料显微结构及力学性能的影响

Effect of SPS sintering process on microstructure and mechanical properties of TiC/6061Al composites

采用低速卧式球磨法和放电等离子烧结法(SPS)制备了2%TiC/6061Al复合材料,利用光学显微镜、扫描电镜、显微硬度仪和拉伸试验研究了不同烧结温度和压力对该复合材料致密度、显微结构和力学性能的影响。结果表明,当烧结温度为500℃时,烧结不充分,颗粒之间结合不紧密,导致复合材料致密度过低;当烧结温度为550℃时,超过了Al基体的熔点,少部分熔融Al飞溅并溢出模具,导致模具内压力不平衡,从而降低了复合材料致密度。复合材料致密度和力学性能随着烧结压力的增大而增大,故选取模具所能承受的最大压力作为最佳烧结压力。故当烧结温度为525℃、烧结压力为40 MPa时,该复合材料的致密度、硬度和强度均达到最大值。

The 2%TiC/6061Al composites were prepared by low-speed horizontal ball milling and spark plasma sintering(SPS).The effects of different sintering temperatures and pressures on the density,microstructure and mechanical properties of the composites were studied by optical microscope,scanning electron microscope,microhardness tester and tensile test.The results show that when the sintering temperature is 500℃,the sintering is not sufficient,and the binding between the particles is not close,which leads to low density of the composite material.When the sintering temperature is 550℃which exceeds melting point of Al matrix,a small amount of molten Al splashes and overflows the mold,resulting in unbalanced pressure in the mold,thereby reducing the density of the composite material.The density and mechanical properties of the composites increase with increase of the sintering pressure,so the maximum pressure that the mold can withstand is selected as the optimal sintering pressure.Therefore,when the sintering temperature is 525℃and the sintering pressure is 40 MPa,the density,hardness and strength of the composite material reach the maximum values.