Effects of Mechanical Ball Milling Time on the Microstructure and Mechanical Properties of Mo2NiB2-Ni Cermets.

Lei Zhang,Zijun Ren,Yangzhen Liu,Yongxin Jian,Kemin Li,Zhen Cao,Zhifu Huang,Yupeng Shen

doi:10.3390/ma12121926

Lei Zhang, Zijun Ren + Show 6 more

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https://doi.org/10.3390/ma12121926

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Abstract

Mo2NiB2-Ni cermets have been extensively investigated due to their outstanding properties. However, studies have not systematically examined the effect of the powder milling process on the cermets. In this study, Mo, Ni, and B raw powders were subjected to mechanical ball milling from 1 h to 15 h. XRD patterns of the milled powders confirmed that a new phase was not observed at milling times of 1 h to 15 h. With the increase in the mechanical ball milling time from 1 h to 11 h, raw powders were crushed to small fragments, in addition to a more uniform distribution, and with the increase in the mechanical ball milling time to greater than 11 h, milled powders changed slightly. Mo2NiB2-Ni cermets were fabricated by reaction boronizing sintering using the milled powders at different ball milling times. The milling time significantly affected the microstructure and mechanical properties of Mo2NiB2-Ni cermets. Moreover, the Mo2NiB2 cermet powder subjected to a milling time of 11 h exhibited the finest crystal size and the maximum volume fraction of the Mo2NiB2 hard phase. Furthermore, the cermets with a milling time of 11 h exhibited a maximum hardness and bending strength of 87.6 HRA and 1367.3 MPa, respectively.

Highlights

Mo2 FeB2, Mo2 NiB2, and WCoB-based cermets have been successfully fabricated by reaction boronizing sintering [1,2,3,4], generating a ternary boride hard phase by liquid-phase sintering.Boride cermets can be prepared by using a metal binder phase
Mo2 NiB2 -Ni cermets [5,6], comprising the Mo2 NiB2 hard phase that contributes to the hardness and the Ni binder phase that contributes to the toughness
A new newphase phaseoror a mechanical alloy is detected not detected during the milling of Mo, and B

Summary

Introduction

Mo2 FeB2 -, Mo2 NiB2 -, and WCoB-based cermets have been successfully fabricated by reaction boronizing sintering [1,2,3,4], generating a ternary boride hard phase by liquid-phase sintering.Boride cermets can be prepared by using a metal binder phase. Mo2 NiB2 -Ni cermets [5,6], comprising the Mo2 NiB2 hard phase that contributes to the hardness and the Ni binder phase that contributes to the toughness These cermets have attracted considerable attention due to their excellent abrasion resistance, anti-oxidation properties, and superior corrosion resistance [7,8]. With those unique properties, Mo2 NiB2 -Ni cermets exhibit good prospects for engineering materials in wear- and erosion-resistant applications, and cermets are expected to replace conventional materials, including nickel-based alloys in injection molding machine parts and copper alloys in pumps used in oil extraction and transport

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