搅拌摩擦加工制备羟基磷灰石增强镁复合材料的微观组织和力学性能

Microstructure and mechanical properties of hydroxyapatite reinforced magnesium composites prepared by friction stirring processing

通过搅拌摩擦加工(Friction stir processing,FSP)制备了羟基磷灰石增强镁(HA/WE43)复合材料,研究了主轴转速对HA分布的影响及FSP加工前后材料微观组织和力学性能的变化。使用光学显微镜、SEM、TEM对该复合材料的显微组织进行了表征,同时对其显微硬度和室温拉伸性能进行了测试。结果表明:制得的HA/WE43复合材料晶粒尺寸相比于母材发生了显著的细化,加工过程中,HA颗粒的存在增强了FSP的晶粒细化作用;主轴转速较低时,HA/WE43复合材料中的HA团聚较严重,随着主轴转速的增加,HA的分布更加均匀,团聚现象得到改善;尽管局部团聚的HA颗粒会成为复合材料在拉伸变形过程中的裂纹源,但HA/WE43复合材料的极限抗拉强度、屈服强度和伸长率相对于母材仍有明显提高。

Hydroxyapatite(HA)reinforced WE43magnesium composites(HA/WE43)were prepared by friction stir processing(FSP),the influence of rotation speed on HA distribution and the changes of microstructure and mechanical properties before and after FSP were studied.The microstructure of HA/WE43composites was characterized by optical microscope,SEM and TEM,and the microhardness and tensile properties tests were conducted to evaluate the mechanical properties.The results show that the grain size of HA/WE43composites is significantly finer than that of the base materials.During the processing,the presence of HA particles enhances the grain refinement effect of FSP.HA particles tend to cluster in the HA/WE43composites prepared at a relatively low rotation speed.As the rotation speed increases,the HA particles distribute more uniform and the agglomeration phenomenon is improved.Although locally agglomerated HA particles can become the origin of cracks in the composite during tensile deformation,an improvement of ultimate tensile strength,yield strength and elongation is achieved in the HA/WE43composites.