机械冲击包覆工艺对SiCp/Fe复合材料组织性能的影响

Effects of Mechanical Impact Metal Coating on Properties and Microstructure of SiCp/Fe Composites

提出了粉末冶金制备颗粒增强铁基复合材料的机械冲击包覆工艺,研究了工艺参数对复合材料组织和性能的影响.结果表明,当球料质量比5∶1,行星球磨机转速225 r/min,冲击包覆120 min时,可以避免机械合金化损伤强化粒子或基体,并能实现基体对强化粒子的最佳包覆.新工艺改善了复合材料中增强粒子分布的均匀性,并且增强体含量越高,机械冲击包覆对提高制备复合材料性能的效果越显著.机械冲击包覆使增强粒子镶嵌进入铁粉颗粒中,避免了复合材料中因增强粒子相互接触而产生的界面缺陷,利于载荷从基体向增强粒子传递,因而复合材料的力学性能得到了提高.

A mechanical impact metal coating technology was developed during powder blending by a mechanical alloying ball mill and the optimal balling parameters of the technology were investigated to manufacture SiCp/Fe composites by hot press process. The results showed that the damage to reinforcing particles or matrix during mechanical alloying can be avoided and the reinforcing particles can be coated by the matrix metal with ball-to-powder ratio of 5： 1, rotational speed of 225 r/min and coating time of 120 min. The new technology can improve the distribution of the particulate reinforcements in the composites and shows the stronger effect as the higher volume fraction of the particulate reinforcements in the composites. The properties of the composites are also improved significantly by the new powder blending technology. Microstructure observations indicate that the reinforcing particles are impacted into the iron powder and the decrease in interfacial defects between the particles contributes to the load transfer from the matrix to particles, so that the mechanical properties of the composites are improved by the technology.