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Abstract: Solidification microstructure of a cast stainless steel containing 1.5–2.5 wt.%B has been examined by means of the optical microscopy (OM), the scanning electron microscopy (SEM), the electron probe microanalyzer (EPMA), energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD) and Vickers microhardness. The as-cast microstructure consists of the M2(B,C) borocarbide and the austenite. The borocarbide is continuously distributed over the austenite. There are some broken-networks in the local location of borocarbide. Moreover, the distribution of alloy elements is not homogeneous in the cast B-bearing stainless steel. Boron element is mainly distributed over the borocarbide, carbon element is mainly distributed over the matrix. Chromium element is mainly distributed over the borocarbide, and there are also some chromium elements in the matrix. Nickel element is mainly distributed over the matrix and silicon is insoluble in the borocarbide. [Copyright &y& Elsevier]

Abstract: The effects of rare earth (RE) on the microstructures and properties of the Fe–5% V–5% W–5% Mo–5% Cr–3% Nb–2% Co–2% C (Fe–V–W–Mo) alloy are investigated. Modification of the Fe–V–W–Mo alloy is effectively achieved through the addition of suitable amount of RE, which refines the prior-austenite grains and eutectic structure. The as-cast microstructure shows that the flake carbides in the eutectic structure become short and fine. After hardening treatment, most of the eutectic carbides are spheroidized and uniformly distributed. The hardness and hot hardness of the modified Fe–V–W–Mo alloy are slightly increased, while the impact toughness is increased by 37.81% and reaches 10.17J/cm2. The rolls made of modified Fe–V–W–Mo alloy show excellent service properties in high speed wire mills, including the prevention of cracks and spalling. [Copyright &y& Elsevier]

Highlights: [•] The as-received microstructure of bulk Fe2B comprises iron and silicon borides. [•] The orientation of Fe2B in liquid zinc strongly affects on corrosion resistance. [•] The Fe2B/FeB phase transition process of bulk Fe2B in liquid zinc occurs. [•] Phase transition and spalling dominate corrosion of Fe2B in liquid zinc. [Copyright &y& Elsevier]

Two-body abrasive wear behavior and mechanism of Fe B alloys with different Mo contents have been systematically investigated. The results show that the Mo addition can promote the formation of Mo-rich and Cr-rich M 2 B in Fe B alloys, and the Mo-rich and Cr-rich M 2 B possess the higher H (hardness) and δ A (plasticity factor) compared to the Fe-rich M 2 B. Meanwhile, with the increase of Mo content, the V Mo+Cr / V Fe increases slightly firstly and then increases rapidly (Where the V Mo , V Cr and V Fe represents the volume fractions of Mo-rich, Cr-rich and Fe-rich M 2 B, respectively, and the V Mo+Cr shows the volume fractions of V Mo and V Cr). The wear results reveal that the wear rate decreases greatly with the increasing V Mo+Cr / V Fe , especially when the V Mo+Cr / V Fe < 0.42. During the two-body wear process, the main wear mechanism is microcutting, and the Mo-rich and Cr-rich M 2 B provide better resistance to the SiC abrasive relative to the Fe-rich M 2 B. In this case, the increasing V Mo+Cr / V Fe induced by the Mo addition contributes to the improvement of the abrasion resistance of Fe B alloys effectively. • The Mo addition results in the formation of Mo-rich and Cr-rich M 2 B in Fe-B alloy. • The Mo-rich and Cr-rich M 2 B possess higher H and δ A compared to the Fe-rich M 2 B. • The Mo-rich and Cr-rich M 2 B can provide better resistance to the SiC abrasive compared to the Fe-rich M 2 B. • The increasing V Mo+Cr / V Fe induced by the Mo addition facilitates the improvement of the abrasion resistance of Fe-B alloy effectively. [ABSTRACT FROM AUTHOR]

Abstract Based on the Fe Cr B alloy, the Fe 12Cr 1.5B xAl (x = 0, 2, 4, 6 and 8 wt%) alloys were designed by adding Al. The as-cast microstructure and cyclic oxidation behavior have been investigated extensively in this study. The results reveal that the as-cast microstructure of Fe Cr B alloy consists of martensite (bcc), retained austenite (orthorhombic) and M 2 (B,C)-bct, M 7 (C,B) 3 -hcp, M 23 (C,B) 6 -complex fcc boron-carbides, gradually changing to α-(Fe,Al,Cr) solid solution (bcc), M 2 (B,C)-bct, M 7 (C,B) 3 -hcp, M 23 (C,B) 6 -complex fcc boron-carbides and Fe 3 Al intermetallic compound with the increasing of Al contents. The oxidation kinetics of all alloy samples follow a parabolic oxidation kinetic law. The oxidation rate constant k p in Al-free Fe Cr B alloy is nearly four times of that in Fe Cr B 8Al alloy. The additions of Al refine the grains and make the distribution of elements more uniform, which results in forming a continuous and dense oxide film containing Al 2 O 3 oxide with excellent fluidity and thermal stability, remarkably enhancing the high temperature oxidation resistance of Fe Cr B Al alloy. Highlights • Based on Fe Cr B alloys, a new Fe Cr B Al alloy was designed. • The as-cast microstructure of Fe Cr B Al alloys was investigated. • Cyclic oxidation behavior of the Fe Cr B Al alloys was studied at 1073 K in air. • The oxidation kinetics of the Fe Cr B Al alloys followed the parabolic-rate law. • The Fe Cr B 8Al exhibits the highest oxidation resistance at 1073 K, about four times of Fe Cr B alloy. [ABSTRACT FROM AUTHOR]

The effects of orientation and lamellar spacing on the interface microstructure and corrosion behavior of a directionally solidified (DS) Fe-B alloy in a hot-dip galvanization bath were investigated. The results indicated that the microstructure of the DS Fe-B alloy consisted of oriented α -Fe and Fe 2 B grains. The oriented Fe 2 B with [002] preferred growth orientation displayed low-angle grain boundaries on the Fe 2 B (001) basal plane. The DS Fe-B alloy with Fe 2 B vertical to the corrosion interface possessed the best corrosion resistance to liquid zinc owing to the formation of an interface-pinning multilayer induced by the Fe 2 B orientation. The epitaxially grown columnar ζ-FeZn 13 products were controlled by the geometric constraint of Fe 2 B grain orientation and size, and a mechanism model that explains the interfacial orientation-pinning behavior is discussed in detail. Transmission electron microscopy (TEM) results revealed that the possible orientation relationships of the oriented Fe 2 B and columnar ζ-FeZn 13 products are (001) Fe2B //(−402) ζ-FeZn13 and [002] Fe2B //[110] ζ-FeZn13 . The corrosion damage of the DS Fe-B alloy with Fe 2 B [002] orientation vertical to the corrosion interface in liquid zinc was governed by the competitive mechanisms of Fe 2 B/FeB transformation and microcrack-spallation resistance, which is proposed as being the result of a multiphase synergistic effect in the micro-structures. [ABSTRACT FROM AUTHOR]

In this paper, the effect of heat treatment (760–1060 °C) on tribological behavior of selective laser melted Ti6Al4V alloy against Si 3 N 4 counter-ball under different applied loads was investigated. Results show the wear rate of as-built Ti6Al4V alloy increased firstly and then gradually decreased with increasing the heat-treatment temperature, which obtained the lowest value when the heat treatment temperature was 1060 °C, exhibiting the best wear resistance. The higher applied load led to larger wear rate and lower coefficient of friction. The wear mechanism was strongly dependent on the microstructure transformation, micro-hardness and applied load, which was discussed in detail. • Ti–6Al–4V alloys were fabricated by selective laser melting. • Friction coefficient and wear resistance were optimized by heat treatment. • Higher applied load led to larger wear rate and lower friction coefficient. • Wear mechanism was strongly dependent on the microstructure transformation, micro-hardness and applied load. [ABSTRACT FROM AUTHOR]

• Temperature effect on oxidation resistance of a Fe-Cr-B-Al-C-Mn-Si alloy is studied. • The oxidation resistance is best at 900 °C; it decreases with rising temperature. • The formation mechanism of oxide scale with bilayer/monolayer structure was discussed. • MnCr 2 O 4 oxides promote protective α-Al 2 O 3 oxide formation. • Selective oxidation of Al suppresses outward diffusion of Cr and Mn. The effect of temperature on the oxidation resistance of a novel wear-resistant Fe-10Cr-1.5B-6Al-0.3C-0.8Mn-0.6Si alloy is investigated. The mass growth rate shows that this alloy exhibits superior oxidation resistance at 900 °C. As the oxidation temperature increases from 900 °C to 1100 °C, the structure of the observed oxide scales transforms from a porous bilayer to a flat monolayer, while the oxidation rate increases sharply. The selective oxidation of Al suppresses the outward diffusion of Cr and Mn to form MnCr 2 O 4 oxides in the monolayer oxide scale, thereby decreasing the oxidation resistance at 1100 °C. [ABSTRACT FROM AUTHOR]