摘要
采用高能球磨对M2高速钢粉末进行破碎,然后添加含量(质量分数,下同)为0~10%的碳化钼(Mo_(2)C)粉末,混合均匀后将混合粉末冷压成形,在真空下烧结得到M2钢与Mo_(2)C增强M2钢,研究烧结样品的致密化行为和力学性能,分析Mo_(2)C对M2钢粉末烧结致密化的影响。结果表明,高能球磨对原料粉末的细化可提高粉体的烧结活性,促进压坯在烧结中期的致密化。通过1180℃固相烧结获得近全致密(相对密度>98%)的M2钢与Mo_(2)C增强M2钢。烧结过程中,Mo_(2)C在950℃基本完全与Fe基体反应转变为M6C相,由此带来的反应烧结与活化烧结促进了烧结中期坯体致密度的提高。烧结中后期形成的大量弥散分布的M_(6)C与M_(2)C碳化物可抑制基体晶粒长大,提高烧结体的硬度和抗弯强度。添加10%Mo_(2)C烧结所得M2钢的抗弯强度达到3135 MPa,硬度(HRC)达到59.6。通过原料粉末细化、Mo_(2)C的反应扩散以及金属颗粒的氧化还原反应能有效提高M2高速钢的烧结性能和力学性能,有望为其他难烧结高速钢的制备提供技术参考。
High-energy ball milled M2 high speed steel powder mixed with 0−10%(mass fraction,the same below)Mo_(2)C were cold-pressed and subsequently densified by sintering under vacuum.The densification behavior and mechanical properties of the sintered samples were investigated,and the effect of Mo_(2)C on the sintering densification of M2 steel powder was analyzed.The results show that the refinement of raw material powder by high-energy ball milling can improve the sintering activity of powder and promote the densification of the green compact in the middle stage of sintering.Both M2 steel and Mo2 C reinforced M2 steel with nearly full density(over 98%of theory density)have been obtained at 1180℃by solid state sintering.The Mo_(2)C added to M2 steel powder substantially reacts with Fe matrix and transforms to M6C phase at 950℃,and the reactive sintering and activated sintering can accelerate the densification of the green compacts at the intermediate stage of sintering.A large number of dispersed M_(6)C and M_(2)C carbides formed during the mid and later stage sintering inhibit grain growth of matrix and improve the hardness and bending strength of sintered compacts.Attracting mechanical properties of sintered M2 steel reinforced with 10%Mo_(2)C particles are achieved,showing satisfactory bending strength of 3135 MPa and hardness of 59.6 HRC.The sinter ability and mechanical properties of M2 steel are improved effectively by the raw powders refinement,reaction diffusion of Mo_(2)C and redox reaction of metal particles,which is expected to provide a technical reference for the preparation of other difficult-to-sinter high speed steels.
作者
陈楠
龙学湖
滕浩
李志友
CHEN Nan;LONG Xuehu;TENG Hao;LI Zhiyou(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;Guangzhou Sailong Additive Manufacturing Co.,Ltd.,Guangzhou 510700,China;College of Mechanical Engineering,University of South China,Hengyang 421001,China)
出处
《粉末冶金材料科学与工程》
2022年第2期161-170,共10页
Materials Science and Engineering of Powder Metallurgy
基金
湖南省教育厅科学研究项目(18C0410)。
关键词
高速钢
高能球磨
显微组织
碳化物
烧结性能
high speed steel
high-energy ball milling
microstructure
carbide
sinter ability
