镀铜CNTs/Ti_(3)AlC_(2)增强AZ91D复合材料的制备及机理研究

Preparation and Mechanism Research of Copper-plated CNTs/Ti_(3)AlC_(2) Reinforced AZ91D Composite

采用自蔓延高温合成法制备Ti_(3)AlC_(2)陶瓷粉体,对CNTs粉体、Ti_(3)AlC_(2)粉体进行化学镀铜,表面改性.以镀铜后的CNTs粉体、Ti_(3)AlC_(2)粉体为增强相,AZ91D粉末为基体,采用热压烧结法制备CNTs/Ti_(3)AlC_(2)/AZ91D复合材料.确定复合材料的最佳原料配比为:镀铜后的CNTs∶镀铜后的Ti_(3)AlC_(2)∶AZ91D=1∶25∶74,热压烧结的最佳工艺参数为:压力为35MPa,烧结温度为500℃.测试了复合材料的各项性能,随着CNTs粉体含量的增加,复合材料的密度逐渐减小,硬度先增加后减小.复合材料的力学性能:弯曲强度为342 MPa、压缩强度为427MPa、剪切强度为119MPa,复合材料拉伸强度提高了25.52%,屈服强度提高了122.46%,延伸率提高了33.54%.并分析了影响复合材料性能的U相生成机制、位错强化机制、载荷强化机制等机理.

Ti_(3)AlC_(2) ceramic powders were prepared by self-propagating high temperature synthesis method. The surface of CNTs and Ti_(3)AlC_(2) powders were modified by electroless copper plating.The CNTs/Ti_(3)AlC_(2)/AZ91 D composites were prepared by hot pressing sintering method using copper plated CNTs powder, copper plated Ti_(3)AlC_(2) powder and AZ91 D powder as raw materials.The optimal raw material ratio of the composite was determined as follows: copper-plated CNTs: copper-plated Ti_(3)AlC_(2)∶AZ91 D=1∶25∶74. The optimal process parameters of hot pressing sintering were as follows: the pressure was 35 MPa and the sintering temperature was 500℃.The properties of the composites were tested. With the increase of the content of CNTs powder, the density of the composites decreased gradually, and the hardness increased first and then decreased.The mechanical properties of the composites are as follows: the bending strength is 342 MPa, the compression strength is 427 MPa, the shear strength is 119 MPa, the tensile strength of the composites is increased by 25.52%, the yield strength is increased by 122.46%, and the elongation is increased by 33.54%.The results show that the properties of AZ91 D powders are improved by adding CNTs and Ti_(3)AlC_(2) powders, and its corresponding mechanism is analyzed.