以部分扩散预合金铁-铜-镍-钼-碳粉为原料,利用模壁润滑温压工艺获得高密度压坯,采用烧结硬化处理工艺烧结,研究了冷却速率和碳含量对烧结材料力学性能和显微组织的影响.结果表明:冷却速率对Fe-2Cu-2Ni-1Mo-xC(x=0.6,1.0)材料的力学性能影响显著,其抗拉强度、屈服强度和硬度均随冷却速率增大而提高;在2.8℃·s-1冷却速率时,1.0%C材料的抗拉强度为935 MPa,屈服强度为747 MPa,硬度为298 HB;0.6%C材料的抗拉强度为962 MPa,屈服强度为828 MPa,硬度为285 HB;伸长率均随冷却速率增大而下降;材料的显微组织均为马氏体、贝氏体、珠光体和残余奥氏体等的混合组织,快速冷却下主要为马氏体、贝氏体,慢速冷却时出现少量铁素体;碳含量对马氏体的类型影响较大,1.0%C时主要为片状马氏体,0.6%C时主要为板条马氏体.

Partial diffusion pre-alloyed Fe-Cu-Ni-Mo-C powders were used as raw materials,high density compacts were obtained by die wall lubricated warm compaction technology,then sinter hardening process was utilized.Effects of cooling rate and carbon content on the mechanical properties and microstructure of the sintered materials were studied.The results show that the effect of the cooling rate on the mechanical properties of the Fe-2Cu-2Ni-1Mo-xC(x=0.6,1.0) material was dramatic.Tensile strength,yield strength and hardness of the material increased with the increase of cooling rate.At the cooling rate of 2.8℃·s-1,tensile strength,yield strength and hardness of the material with 1.0% carbon content achieved 935 MPa,747 MPa and 298 HB,respectively.And the material with 0.6% carbon content achieved 962 MPa,828 MPa and 285 HB,respectively.Elongation of both the materials decreased with the increasing cooling rate.The microstructure of the materials consisted of martensite,bainite,pearlite and retained austenite.The microstructure mainly contained martensite and bainite at high cooling rate.When the cooling rate decreased,little ferrite was observed.Carbon content had great effect on the martensite type.Plate and lath type martensite structure formed with 1.0% and 0.6% carbon,respectively.