烧结温度对10TiB/Ti-4.5Al-6.8Mo-1.5Fe复合材料组织与性能的影响

Effect of sintering temperature on microstructure and mechanical properties of 10TiB/Ti-4.5Al-6.8Mo-1.5Fe composite

以Ti、Al、Mo、Fe元素粉末及LaB6和TiB2粉末为原料,采用机械混合法制备钛基复合粉末,经高速压制成形后,分别在1 150、1 250和1 350℃下真空烧结制备以TiB晶须为增强体、钛合金Ti-4.5Al-6.8Mo-1.5Fe为基体的钛基复合材料。借助X射线衍射、金相显微镜和扫描电镜分析材料的物相组成和微观组织,测试复合材料的维氏硬度(HV2.0)和拉伸性能,研究烧结温度对复合材料的组织和力学性能的影响。结果表明:10TiB/Ti-4.5Al-6.8Mo-1.5Fe复合材料的相对密度随烧结温度升高而增加,烧结温度为1 350℃时达到最大值98.9%;TiB晶须的长径比随烧结温度升高显著降低。烧结温度为1 250℃时,该材料的维氏硬度和室温抗拉强度都达到最大值,分别为399HV和1 179 MPa。

TiB whisker reinforced Ti-4.5Al-6.8Mo-1.5Fe titanium matrix composite was fabricated by mechanically mixing the elemental powders of titanium,aluminum,molybdenum,iron,lanthanum hexaboride as well as titanium diboride,and then followed by high-velocity compaction and vacuum sintering at 1 150,1 250 and 1 350 ℃,respectively.The phase composition and microstructure were characterized by X-ray diffractometry（XRD）,optical microscopy（OM） and scanning electron microscopy（SEM）,and the mechanical properties were also tested.The effect of sintering temperature on microstructure and mechanical properties of the samples were discussed.The results show that the relative density of the sintered samples increases with increasing sintering temperature,and the maximum value reaches 98.9% at 1 350 ℃.While the ratio of length to diameter of the TiB whisker decreases remarkedly with increasing sintering temperature.The mechanical properties such as the Vickers hardness（HV2.0） and tensile strength increase firstly and then decrease with increasing sintering temperature,and the maximum values of 399 HV and 1 179 MPa,respectively are obtained sintered at 1 250 ℃.