颗粒原位增强TiB_(2)/ZL205A复合材料的组织与力学性能研究

Study on Microstructure and Mechanical Properties of Particle In-situ Reinforced TiB_(2)/ZL205A Composites

通过混合盐反应内生的方法在ZL205铝合金基体中引入TiB_(2)颗粒增强相,研究TiB_(2)颗粒增强铝合金材料在铸态和热处理后的微观组织和力学性能。研究表明:TiB_(2)颗粒增强ZL205A复合材料的基本相组成为α-Al相、CuAl_(2)相及TiB_(2)颗粒。TiB_(2)颗粒的内生改善了基体和颗粒之间的润湿性,促进分散,同时将颗粒增强体尺寸控制在1μm以下。复合材料坯体挤压时,利用晶粒之间的滑动促进颗粒分散,挤压后再进行热处理,促进了颗粒的进一步分散,使TiB_(2)颗粒团聚现象得以改善,复合材料获得优异的力学性能。室温下,复合材料的极限抗拉强度、屈服强度和弹性模量分别达到598.0 MPa、510.0 MPa和92.4 GPa。在300℃下,复合材料的极限抗拉强度为197.0 MPa,伸长率为5.5%。相比ZL205A基体,复合材料的力学性能得到大幅提高。

The particle-reinforced phase was introduced into ZL205 aluminum alloy matrix by mixing TiB_(2)salt,the microstructure and mechanical properties of TiB_(2)particle reinforced aluminum alloy materials after as-cast and heat treatment were studied.The results show that the basic phase composition of TiB_(2)particle reinforced ZL205A composites isα-Al phase,CuAl_(2)phase and TiB_(2)particles.The endogeneity of TiB_(2)particles improves the wettability between the matrix and particles,promotes dispersion,and controls the particle reinforcement size below 1μm.When the composite billet is extruded,the particles are dispersed by sliding between grains.After extrusion,the heat treatment can promote the further dispersion of particles,improve the agglomeration of TiB_(2)particles,and the composites obtain excellent mechanical properties.The ultimate tensile strength,yield strength and elastic modulus of the composites reach 598.0 MPa,510.0 MPa and 92.4 GPa respectively at room temperature.The ultimate tensile strength of the composites is 197.0 MPa and the elongation is 5.0%at 300℃.Compared with ZL205A matrix,the mechanical properties of the composites are greatly improved.