Solubility of Cu, Ni, Mn in Boron-Rich Fe-B-C Alloys

Abstract

In the present study, the microstructure development and mechanical properties of the cast boron-rich Fe–B–C alloys cooled at 10 and 103 K/s were investigated as functions of alloying elements additions. These alloys were prepared in the following compositional ranges: B (10–14 wt.%), C (0.1–1.2 wt.%), M (5 wt.%), where M – Cu, Ni or Mn, balance Fe. Structural properties were characterized by quantitative metallography, X-Ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. Mechanical properties of the structural constituents, such as microhardness and fracture toughness, were measured by a Vickers indenter. Copper becomes negligibly incorporated into the phases Fe(B,C) and Fe2(B,C) of the Fe–B–C alloys, but solubility limit forces the remaining solute into the residual liquid. As a result, the globular Cu inclusions are seen in the structure. As compared with copper, nickel has higher solubility in the constituent phases, with preferential solubility observed in the Fe2(B,C) crystals, where Ni occupies Fe positions. Having limited solubility, nickel also forms secondary Ni4B3 phase at the Fe2(B,C) boundaries. Manganese was found to dissolve completely in the Fe–B–C alloys forming substitutional solid solutions preferentially with Fe(B,C) dendrites. By entering into the iron borides structure, Mn and Ni improve their ductility but lower microhardness. The peculiarities in the structure formation and properties of the doped boron-rich Fe–B–C alloys were explained with electronic structure of the alloying elements considered.

Effect of Exothermic Addition (CuO - Al) on the Structure, Mechanical Properties and Abrasive Wear Resistance of the Deposited Metal During Self-Shielded Flux-Cored Arc Welding

“…The positive effect on phase sizes reducing during alloying of Fe-B-C alloys with such elements as Cu, Ni and Mn is confirmed by Sukhova V.V. [44].…”

“…As known copper is hardly soluble in Fe2(В,С) and Fe(В,С) phases. It changes micro hardness and crack toughness coefficient of deposited metal very slightly [44].…”

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“…The amount of Cu in the matrix is increased [91] with the addition of Cu, as an anodes substance during corrosion, because the standard potential for the redox couple Cu 2+ /Cu is positive. Cu alloy elements are separated on the sample surface and formed a compact Cu-rich passive film [105] in the atomic scale.…”

“…Cu is a wellknown alloying element used to increase the overall corrosion resistance [86][87][88][89][90]. It is known the copper does not form compounds with boron (B) and remains mostly in the matrix [91], dissolving mostly in austenite [78]. Studies of alloys of the alloying system with a high boron content of 3.5% wt.…”

Investigations of Abrasive Wear Behaviour of Hybrid High-Boron Multi-Component Alloys: Effect of Boron and Carbon Contents by the Factorial Design Method

“…Researchers have attempted to improve the tribological properties of plain Fe-B alloys by adding alloying elements (Cr, Mn, Mo, Ti, etc. ); Cr is most often used [ 35 , 36 , 37 , 38 , 39 , 40 ]. Jian et al [ 35 , 36 ] found that adding 2 wt.% Cr increases the wear resistance of an Fe-3.0 wt.% B alloy under SiC and SiO 2 abrasion; if the Cr content is increased further, the wear resistance decreases.…”