Hou Bo, Wang Aiqin, Liu Pei, Xie Jingpei
College of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, China.
Provincial and Ministerial Co-Construction of Collaborative Innovation Center for Non-Ferrous Metal New Materials and Advanced Processing Technology, Luoyang 471023, China.
Materials (Basel). 2022 Aug 21;15(16):5766. doi: 10.3390/ma15165766.
The TiAlC/TiAl composite with a homogenous architecture was fabricated via spark plasma sintering (SPS) using Ti/Al/GNSs composite powders, after ultrasonic mechanical stirring, as raw materials. The phases, microstructure, compressive properties and Vickers hardness of the composite were methodically characterized. We observed the transformation of graphene nanosheets from multi-layer to few-layer by the ultrasonic dispersion and the uniform distribution of few-layer graphene nanosheets in composite powders by ultrasonic mechanical stirring. The composite is mainly composed of rod-shaped TiAlC particles and a TiAl matrix, and the formation of rod-shaped morphology with the long axis along the (0001) plane is due to the fact that the growth rate of TiAlC parallel to the (0001) plane is much higher than the growth rate along the [0001] direction. The compressive stress and strain of the as-prepared TiAlC/TiAl composite reach 1451.2 MPa and 19.7%, respectively, which are better than some TiAlC/TiAl composites using graphite as the carbon source, and the Vickers hardness remains between 400~500 HV. The fracture morphologies show the deformation and fracture features of TiAlC particles, i.e., lamellae kinking and laminated tearing, which could increase the toughness of TiAl alloys.
采用经超声机械搅拌后的Ti/Al/石墨烯纳米片（GNSs）复合粉末作为原料，通过放电等离子烧结（SPS）制备了具有均匀结构的TiAlC/TiAl复合材料。系统地表征了该复合材料的相组成、微观结构、压缩性能和维氏硬度。通过超声分散，我们观察到石墨烯纳米片从多层向少层的转变，并且通过超声机械搅拌实现了少层石墨烯纳米片在复合粉末中的均匀分布。该复合材料主要由棒状TiAlC颗粒和TiAl基体组成，沿（0001）面长轴方向形成棒状形态的原因是TiAlC在平行于（0001）面方向上的生长速率远高于沿[0001]方向的生长速率。制备的TiAlC/TiAl复合材料的压缩应力和应变分别达到1451.2 MPa和19.7%，优于一些以石墨为碳源的TiAlC/TiAl复合材料，其维氏硬度保持在400~500 HV之间。断口形貌显示了TiAlC颗粒的变形和断裂特征，即片层扭结和层状撕裂，这可以提高TiAl合金的韧性。
