Densification and mechanical properties of ball milled M2 high speed steel powder reinforced with Mo2C
CHEN Nan1, LONG Xuehu2, TENG Hao3, LI Zhiyou1
1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; 2. Guangzhou Sailong Additive Manufacturing Co., Ltd., Guangzhou 510700, China; 3. College of Mechanical Engineering, University of South China, Hengyang 421001, China
Abstract High-energy ball milled M2 high speed steel powder mixed with 0-10% (mass fraction, the same below) Mo2C 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 Mo2C 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 1 180 ℃ by solid state sintering. The Mo2C 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 M6C and M2C 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% Mo2C particles are achieved, showing satisfactory bending strength of 3 135 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 Mo2C 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.
CHEN Nan,LONG Xuehu,TENG Hao, et al. Densification and mechanical properties of ball milled M2 high speed steel powder reinforced with Mo2C[J]. Materials Science and Engineering of Powder Metallurgy, 2022, 27(2): 161-170.
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2022, Vol. 27 
