高能超声时间对原位自生TiB_(2)/Al复合材料组织和性能的影响

Effect of high energy ultrasonic time on microstructure and properties of in-situ TiB_(2)/Al composites

采用原位合成Al-K2TiF6-KBF4熔盐体系,通过熔体反应法成功制备了颗粒增强铝基复合材料。采用扫描电镜、X射线衍射(XRD)、万能力学试验机及摩擦磨损试验等研究了高能超声时间对复合材料的组织、力学性能和摩擦磨损性能的影响。结果表明:复合材料中存在TiB_(2)颗粒和少量Al3Ti颗粒,颗粒大小为1~2μm,TB_(2)颗粒的截面形貌接近于正六边形,且在基体中均匀分布。复合材料的抗拉强度和伸长率随着超声处理时间的增加而提高。当超声时间为4 min时,复合材料的抗拉强度和伸长率达到最大值,分别为172 MPa和11.1%,比A356母合金分别提高了20.3%和126%,断裂模式也从准解理断裂转为韧性断裂,耐磨性也相对最好,摩擦系数达到最小值0.44,磨损量为-0.5 mg。

Particle reinforced aluminum matrix composites were fabricated by reaction in melt method using in situ Al-K2TiF6-KBF4 molten salt system,and the effects of high-energy ultrasonic time on microstructure,mechanical properties and friction and wear properties of the composites were investigated by means of scanning electron microscopy,X-ray diffraction(XRD),universal mechanical testing machine and friction and wear test.The results show that there are TiB_(2) particles and a small amount of Al3Ti particles in the composites,the particle size is 1-2μm,the cross section morphology of the TB_(2) particles is close to the regular hexagon,and uniformly distribute in the matrix.The tensile strength and elongation of the composites increase with the increase of ultrasonic treatment time.When the ultrasound time is 4 min,the tensile strength and elongation of the composites reach the maximum,which are 172 MPa and 11.1%,respectively,which are 20.3%and 126%higher than that of the A356 alloy matrix,the fracture mode also changes from quasi-cleavage fracture to ductile fracture,the wear resistance is also relatively good,the friction coefficient reaches the minimum value of 0.44,and the wear amount is-0.5 mg.