【摘要】 采用真空电弧熔炼制备了多尺度Ti₂AlC/TiAl复合材料。微观结构表明，在全片层TiAl基体的晶界处原位析出微米级Ti₂AlC颗粒。通过热处理工艺，微纳米级Ti₂AlC在层片状TiAl/Ti₃Al相界处定向析出，同时，纳米级Ti₂AlC在TiAl晶内定向析出。当石墨粉的添加量为2%（摩尔分数）时，复合材料展现出最优的高温拉伸性能，抗拉强度达到561 MPa，伸长率为3.6%。结果表明，多尺度Ti₂Al C在提高材料性能方面发挥多重协同效应：微米级Ti₂AlC可以有效抑制晶界软化并阻碍位错运动，微纳米级Ti₂AlC则能够阻止孪晶扩展并阻碍位错运动，纳米级Ti₂AlC不仅能阻碍位错运动，还能细化层片状显微组织。更多还原

【Abstract】 The multi-scale Ti₂ AlC/TiAl composites were fabricated. Micro-Ti₂ AlC particles are obtained in-situ at the grain boundaries of the full lamellar TiAl matrix by vacuum arc melting. The targeted precipitation of submicro-Ti₂ Al C at the lamellae TiAl/Ti₃ Al phase boundary and directional precipitation of nano-Ti₂ AlC within TiAl crystals are achieved by heat treatment. And the best high-temperature tensile properties are obtained when the graphite powder is added at 2 at.%, resulting in a tensile strength of 561 MPa and an elongation of 3.6%. These findings underscore the multifaceted role played by the multi-scale Ti₂ AlC: micro-Ti₂ AlC effectively inhibits grain boundary softening and hinders dislocation motion, while submicro-Ti₂ AlC prevents twin propagation and obstructs dislocation motion. Nano-Ti₂ AlC, on the other hand, not only hinders dislocation movement but also fine-tunes the lamellar microstructure.更多还原