预扩散处理Cr-Fe粉对铁基合金组织与性能的影响

Influence of pre-diffusion treatment of Cr-Fe powders on the microstructure and properties of iron-based alloys

以水雾化纯Fe粉为基体粉末,研究含Cr铁粉与纯Fe粉在不同温度下预扩散处理对铁基合金组织与性能的影响。结果表明:采用预扩散处理可以提高Cr元素的强化效果,优化合金性能;在Cr-Fe粉预扩散温度为750℃、800℃、820℃时,铁基合金的密度随着预扩散温度的升高而提高,预扩散温度为850℃时,合金密度明显降低;铁基合金热处理后的硬度随着Cr-Fe粉预扩散温度的升高而增大;抗拉性能随着Cr-Fe粉预扩散温度的升高而略有降低,在850℃预扩散处理后下降明显。未经预扩散处理的铁基合金,其显微组织主要为铁素体、马氏体以及少量珠光体,经预扩散处理后,合金主要由马氏体和铁素体组成,且马氏体的含量随着预扩散温度的升高而增加。由含Cr铁粉与基体粉末在800℃左右扩散处理后的粉末制备的铁基烧结合金,其硬度可以达到30HRC以上,抗拉强度保持在780MPa以上。

The effects of different pre-diffusion treatment temperatures of Cr-Fe alloy powder and base powder on microstructure and properties of the alloys were observed by using water atomized iron powder as base powder in the paper. Results indicate that when the pre-diffusion temperatures are 750℃ , 800℃ and 820℃ ,the green density and sintered density increase with the increasing pre-diffusion temperature, then density declines at 850℃ ; hardness increases with increasing pre-diffusion temperature; the tensile strength slightly decreases as the pre-diffusion temperature increasing and obviously decreases at 850℃. Without pre-diffusion treatment, the microstructure of the alloys consists of ferrite, martensite and a small amount of pearlite, while the main structure of the alloys consists of martensite and ferrite with pre-diffusion treatment, and the martensitic amount increases with pre-diffusion temperature increasing. The hardness of sintered samples prepared by the ferro-chrome powder and base powder pre-diffusion treated at 800℃ can reach more than 30HRC,while tensile strength keeps above 780MPa.