挤压温度对TC4_(p)/ZK60复合材料组织及性能的影响

Influence of Extrusion Temperature on Microstructure and Properties of TC4_(p)/ZK60 Composites

采用熔体搅拌及压力下铸造工艺,制备了TC4_(p)/ZK60镁基复合材料,并对其进行了热挤压,研究了挤压温度对TC4_(p)/ZK60镁基复合材料组织及力学性能的影响。结果表明,TC4_(p)在制备过程中发生部分溶解,部分Ti和V扩散至Mg基体中,但是Ti与V并未与基体元素形成新相。Zn倾向于在TC4_(p)与基体之间的界面处富集,生成大量细小的MgZn2相。通过挤压变形后,复合材料内部发生部分再结晶,不同挤压温度下TC4_(p)颗粒周围的再结晶程度不同,沿挤压方向的再结晶程度高于垂直挤压方向。在200~300℃内,随挤压温度升高,复合材料的再结晶程度增加,Mg基体的平均晶粒尺寸增大,复合材料的强度逐渐降低,伸长率逐渐升高。当挤压温度为200℃时,TC4_(p)/ZK60复合材料的抗拉强度和屈服强度分别为394.6 MPa和353.6 MPa,伸长率为2.8%。

TC4_(p)/ZK60 magnesium matrix composites were prepared by melt stirring casting,and effects of extrusion temperature on microstructure and properties of TC4_(p)/ZK60 magnesium matrix composites were investigated.The results indicate that a portion of TC4_(p)is dissolved during the process,and partial Ti and V elements are diffused into Mg matrix,which fail to form new phases with the elements in matrix.Zn element tends to accumulate at the interface between TC4_(p)particles and the substrate to generate a large number of fine MgZn2 phase.After extrusion,partial recrystallization occurs inside the composites,and the degree of recrystallization around the particles varies with the extrusion temperature,exhibiting a higher degree of recrystallization along the extrusion direction than that of ones along perpendicular direction.Within 200~300℃,the degree of recrystallization of the composites and grain size are increased as extrusion temperature increases,leading to a reduction in strength and rise in elongation.When the extru⁃sion temperature is 200 oC,the tensile strength,yield strength and elongation of TC4_(p)/ZK60 composites reach 394.6 MPa,353.6 MPa and 2.8%,respectively.