摘要
Ti_(2)AlC/TiAl composites with a network structure were successfully prepared with carbon nanotubes and Ti-45Al-8Nb pre-alloyed powder using spark plasma sintering.The effects of sintering temperature(1200-1350℃)on the microstructural evolution and mechanical properties were systematically investigated.The microstructure of Ti_(2)AlC/TiAl composites exhibits duplex,near-lamellar,and fully lamellar structures,as the sintering temperature increases from 1200 to 1350℃.The network structured Ti_(2)AlC phase can refine the microstructure and the phase becomes discontinuous at high sintering temperatures.Notably,composites sintered at 1300℃ exhibit excellent mechanical properties,with the highest compressive strength(1921 MPa)and fracture strain(26%)at room temperature.Moreover,the ultimate tensile strength and fracture strain reach 537 MPa and 3.1%at 900℃,and 485 MPa and 3.3%at 950℃,respectively.The enhancement of the mechanical properties is attributed primarily to the load bearing,particle pull-out,and inhibition of crack propagation induced by Ti_(2)AlC particles.
利用碳纳米管和Ti−45Al−8Nb预合金粉末为原料,通过放电等离子烧结成功制备了具有网络结构的Ti_(2)AlC/TiAl复合材料。系统研究了烧结温度(1200~1350℃)对显微组织演变和力学性能的影响。结果表明,随着烧结温度从1200℃升至1350℃,复合材料显微组织呈现双态、近片层和全片层结构。网状结构的Ti_(2)AlC相能够细化组织,且随着温度的升高而变得不连续。在1300℃下烧结的复合材料表现出最高的抗压强度和断裂应变,分别为1921 MPa和26%。此外,复合材料在900℃时的极限拉伸强度和断裂应变为537 MPa和3.1%,在950℃时仍然高达485 MPa和3.3%。Ti_(2)AlC承载载荷、颗粒拔出和抑制裂纹扩展是提高复合材料力学性能的主要原因。
基金
financially supported by the National Natural Science Foundation of China(Nos.52171120,52271106,52071188)
the Natural Science Foundation of Zhejiang Province,China(No.LZY23E050001)。
