Cu、C添加量对退火态Fe-1.75Ni-0.50Mo粉末烧结合金组织和力学性能的影响  

The influence of C and Cu addition and annealing of prealloyed iron powders on the mechanical properties and microstructure of sintered Fe-1.75Ni-0.50Mo alloys

作　　者：张德金 罗丰华[1,2] 高翔[2] 王翔[2] 雷龙林[2] 崔建民 

机构地区：[1]莱芜钢铁集团粉末冶金有限公司,山东莱芜271105 [2]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金技术》2011年第2期125-129,136,共6页Powder Metallurgy Technology

基　　金：国家科技支撑计划项目(2009BAE74B02);粉末冶金国家重点实验室创新基金项目(200902)

摘　　要：将水雾化制备的Fe-1.75Ni-0.50Mo预合金粉在860℃下退火1h,分别添加质量分数为0.4%、0.6%、0.8%的C和1.2%、1.6%、1.8%的Cu;600MPa下压制成形后,在氢气保护下烧结3h,烧结温度为1 160℃。测定了合金的力学性能,并进行金相显微组织观察和拉伸断口形貌分析。研究结果表明:退火处理能够改善预合金粉末的压缩性,压坯密度可达7.18g/cm3;随着C、Cu含量的增加可促使合金组织中出现贝氏体和马氏体组织,从而提高合金的硬度和强度,含1.6%Cu、0.8%C的烧结合金抗拉强度达到772MPa,其显微组织为珠光体+贝氏体;C、Cu含量过高,虽然形成高硬度的马氏体组织,但导致晶粒粗化、孔隙增多,从而使合金强度下降。Water atomized Fe-1.75Ni-0.50Mo prealloyed powders were annealed for 1h at 860℃.Carbon addition values were 0.4%、0.6%、0.8% and copper additive values were 1.2%、1.6%、1.8% Cu in weight percent.The premixes were compacted by conventional die pressing with 600MPa pressure.Alloys were sintered 3h at 1 160℃ in H2 atmosphere.Hardness and tensile properties of the alloys were tested and discussed by means of their microstructures and fractographs.The results show that the compressibility of the premixed powders increases by annealing.Thereby,the microstructure and mechanical properties of the alloys have been improved.The maximum density of the alloys is 7.18g/cm3.The additions of copper and graphite bring the appearance of high strength structure,such as bainite and martensite,leading to the increase of hardness and tensile strength.The tensile strength of the alloy with 1.6% copper and 0.8% graphite reach to 772MPa with pearlite and bainite mixed microstructure.Martensite appears in the microstructure of alloys in excess value of C and Cu content,leading to coarsening of grain size and increase of porosity and so the tensile strength decrease.

关 键 词：铁基合金 预合金粉 拉伸性能 

分 类 号：TF124.5[冶金工程—粉末冶金]