采用机械合金化+热压工艺路线来制备化学计量比成分的单相Laves相TaCr2合金.研究了热压烧结温度(1250、1300、1350、1400℃)及保压时间(0.5、1、2、3h)对合金组织和室温力学性能的影响.结果表明:热压烧结后的合金由Laves相TaCr2和微量Ta、Cr三相组成.热压温度对Laves相TaCr2合金晶粒度和致密度的影响大于保压时间.TaCr2合金的维氏硬度值随保压时间延长而降低,1400℃×1 h热压合金的维氏硬度最大,达9.75 GPa.1350℃和1400℃热压合金的断裂韧性随热压时间延长而减小.1300 ～1400℃热压烧结下合金的断裂韧性随着热压温度增加呈下降的趋势,1300℃ x3 h热压烧结合金断裂韧性值最高,为4.39 MPa· m1/2.
Laves phase TaCr2 alloys with a stoichiometric composition were prepared by mechanical alloying followed by hot pressing.Effects of hot-pressing temperatures (1250,1300,1350,1400 ℃) and time(0.5,1,2,3 h) on microstructure and room-temperature mechanical properties of the alloys were investigated.The results show that the hot-pressed alloys are mainly composed of three phases including TaCr2,Ta and Cr.The effect of hot pressing temperature on the grain size and density of the Laves phase TfaCr2 alloy is greater than the holding time.The hardness of the TaCr2 alloy is decreased with the increase of hot-pressing holding time,and the highest hardness of 9.75 GPa of the alloy is obtained after hot-pressing at 1400 ℃ for 1 h.Moreover,the fracture toughness of the alloys hotpressed at 1350 ℃ and 1400 ℃ both decreases with increasing hot-pressing time.The highest fracture toughness of 4.39 MPa·m1/2 of the alloy is obtained after hot-pressing at 1300 ℃ for 3 h.
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