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利用Ti与La B6之间的化学反应经普通的熔铸工艺原位合成了Ti B和La2O3增强的钛基复合材料,而后复合材料浇铸成20 mm的棒材。研究了α+β和β热处理对复合材料的组织和拉伸性能的影响,利用光学显微镜和扫描电镜研究热处理后材料的微观组织和拉伸试样断面上增强体的增强机制。结果表明,α+β热处理后复合材料为α+β片层与少量近等轴α的混合组织,β热处理后复合材料为网篮组织。β热处理后复合材料的室温抗拉强度为1190 MPa,比α+β热处理的提高了31 MPa;β热处理后复合材料在600℃的抗拉强度为793 MPa,比α+β热处理的提高了48 MPa。复合材料在室温和600℃的断裂机制为Ti B纤维的承载断裂,在650℃和700℃的断裂机制为Ti B纤维的承载断裂和少量脱粘。
The Ti-based and La2O3-reinforced Ti-based composites were synthesized in-situ by the common casting process with the chemical reaction between Ti and LaB6, and then the composites were cast into 20 mm bars. The effects of α + β and β heat treatment on the microstructure and tensile properties of the composites were studied. The microstructure of the material after heat treatment and the enhancement mechanism of the reinforcements on the tensile specimens were studied by optical microscope and scanning electron microscope. The results show that α + β composite is a mixed microstructure of α + β sheet and a small amount of near-equiaxed α, and the β-heat-treated composites are baskets. The tensile strength of the composite at room temperature was 1190 MPa after β heat treatment, which was 31 MPa higher than that of the α + β heat treatment. The tensile strength of the composite at 79 ℃ of 793 MPa after β heat treatment was 48% higher than that of α + β heat treatment MPa. The fracture mechanism of the composites at room temperature and 600 ℃ is the load-bearing fracture of TiB fibers. The fracture mechanism at 650 ℃ and 700 ℃ is the bearing fracture of TiB fibers and the small amount of debonding.