磁化学原位合成制备ZrB_(2p)/A356复合材料及其表征

In-situ Synthesized ZrB_(2p)/A356 Composites by Magnetic-Chemical Reaction and Its Characterization

采用磁化学原位反应技术,以A356-K_2ZrF_6-KBF_4为反应体系成功制备出ZrB_2颗粒增强A356基复合材料;采用XRD、SEM和拉伸试验机对该复合材料的物相组成、显微组织和力学性能进行了研究。结果表明:反应生成的ZrB_2颗粒尺寸为1.0～1.3μm,颗粒形貌为规则六方体,分布均匀;相对于常规的原位反应方法,脉冲磁场能有效促进化学反应的进程,阻止颗粒的团聚长大,使颗粒分布更加均匀;该复合材料的抗拉强度达到273.1 MPa,较未施加脉冲磁场的223.5 MPa提高了22.19%,伸长率略有下降;室温拉伸断口表现出明显的韧窝断裂特征,为塑性断裂。

ZrB_2 particle reinforced A356 matrix composites were prepared using A356-K_2ZrF_6-KBF_4 as reaction system by magnetic-chemical in-situ reactive synthesis method.Phase composition,microstructure and mechanical properties of the composite were investigated by means of XRD,SEM and tensile test machine.The results show that the obtained ZrB_2 particles with average size of 0.1—0.3μm had regular hexagonal morphology and distributed uniformly in the matrix alloy.Compared with the traditional in-situ reaction,the pulse magnetic field could effectively improve the chemical reaction process,prevent the particles agglomeration and growth,make the particles distributed more uniformly.The tensile strength of the composites reached 273.1 MPa,which was increased by 22.19%compared with that of the composites without pulse magnetic filed（223.5 MPa）.And the elongation reduced.The obvious dimple-crack characteristics on the tensile fracture surface at room temperature of the composites were observed,and the fracture mechanism was plastic fracture.