Mechanical Alloying as an Effective Way to Achieve Superior Properties of Fe–Co–Ni Binder Alloy

Pavel Loginov,Mikhail Petrzhik,Evgeny Levashov,Daria Sidorenko,Marina Bychkova

doi:10.3390/met7120570

Abstract

This study addresses the fabrication of nanocrystalline Fe–Co–Ni alloy using two operations: mechanical alloying (MA) of elemental powders and hot pressing (HP). The evolution of the phase composition and structure of the powder particles after MA was investigated. Ball milling with rotation speed 700 rpm for 15–20 min allows the production of a bcc Fe-based supersaturated solid solution. During the HP of this powder, this solution decomposes into a bcc (Fe) solid solution and fcc Fe3Ni precipitates, which act as a recrystallization barrier at elevated temperatures. This factor, along with the solid solution strengthening of the (α–Fe) matrix and high concentration of lattice defects (dislocations and twins), provides high mechanical properties (ultimate bending strength of 2000 MPa and hardness of 108 HRB) and wear resistance of the alloy. The developed Fe–Co–Ni alloy is promising for use as a binder in diamond tools designed for machining abrasive materials.

Highlights

Diamond tools are widely used in the construction and mining industries
X-ray powder diffraction (XRD) patterns recorded for the Fe–Co–Ni powder mixtures treated in the Turbula mixer and in the planetary ball mills (PBMs) for different times were examined to analyse the features of the phase formation during Mechanical alloying (MA)
In the XRD patterns of these powder mixtures, the peaks from Ni shifted towards smaller 2θ angles demonstrating that the lattice parameter of this phase increased and Fe was dissolved in this phase [30]

Summary

Introduction

Diamond tools are widely used in the construction and mining industries. The working layer of these tools is typically made of a composite material: diamond grains (or any other ultrahard materials such as cubic boron nitride) surrounded by the metal matrix (the binder). Co has been conventionally considered to be the best material for manufacturing binders due to the combination of high mechanical properties and wear resistance as well as its ability to firmly hold diamond grains within the working layer [1,5]. Its high cost and toxicity have forced tool manufacturers to seek other materials to fabricate binders that possess similar parameters [6,7]. This problem has been partially solved by using low-cobalt or cobalt-free alloys based on Fe, Ni, and Cu with physical, chemical, and mechanical properties that are similar to those of Co [8,9,10]. Binders for cutting tools with strength not inferior to Co have been designed by varying the compositions in Fe–Cu–Co [11], Fe–Cu–Sn [12], Fe–Ni–Cu–Sn–C [13], and Ni–Cr–P [14] systems and selecting the optimal mixing and compaction regimes

Objectives

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Results

Conclusion