热处理对粉末冶金温压铁基合金组织和性能的影响

The effect of heat treatment on the microstructure and mechanical properties of iron based P/M materials

采用粉末内润滑温压技术制备了Fe-3.5Ni-1.95Cu-0.54Mo-1C合金与Fe-3.81Ni-1.56Cu-0.48Mo-0.25C合金,并对烧结试样进行了渗碳淬火和回火热处理.通过对烧结试样和热处理试样的密度及组织的对比分析,研究了热处理对温压铁基合金的显微组织和机械性能的影响.结果表明:烧结态Fe-3.81Ni-1.56Cu-0.48Mo-0.25C合金经热处理后,其抗拉强度可由640MPa提高到1044MPa,表观硬度可由88HRB提高到46HRC,显微组织为回火马氏体和残余奥氏体,它的烧结态断裂机制属于韧性断裂和解理断裂共存的混合型断裂,而热处理态合金的断裂机制为脆性准解理断裂.

Abstract： Fe-3.5Ni-1.95Cu-0.54Mo-lC alloy and Fe-3.81Ni-1.56Cu-0.48Mo-0.25C alloy were fabricated by powder lubrication warm compaction, and then the sintered specimens were heat-treated with quenching and tempering. The influences of the heat-treatment on the microstructure and mechanical properties of the P/M iron-based materials were investigated. The results show that with the application of heat-treatment after sintering, mechanical properties of two kinds of materials are enhanced obviously. For Fe-3.81Ni- l. 56Cu-0.48Mo-0.25C alloy, the ultimate tensile strength is increased from 640MPa to 1044MPa, the hardness is increased from 88 HRB to 46 HRC, and the microstructure is of tempered martensite and retained austenite. The sintered alloy shows a dimpled and cleavage fracture surface,and the fracture mechanism of heat-treated alloy is quasi-cleavage brittle fracture mode.