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Abstract In this work, the high temperature wear behavior of Ca Ti modified high-boron high-speed steel is investigated. The results indicate that the microstructure of the alloy consists of matrix and eutectic borocarbide. Ca Ti modification aims at improving the stability of borocarbide under wear condition through making the distribution of borocarbide more isolated. The wear experiment revealed that the wear resistance of high-boron high-speed steel is much better than that of T15 steel due to the better oxidization resistance and mechanical property of matrix and borocarbide respectively. Under 25 °C and 200 °C, main wear mechanism of high-boron high-speed steel is adhesive spalling. When the temperature is 400 °C, the mechanism becomes combination of adhesive spalling and oxidization. Under 600 °C, the mechanism is oxidation. Highlights • Borocarbide in Ca Ti modified high boron high speed steel is remarkably refined and spheroidized. • Wear resistance of high boron high speed steel is much better than that of T15 high vanadium high speed steel. • Worn surface roughness of high boron high speed steel after high-load and long-time wear process is quite low. [ABSTRACT FROM AUTHOR]

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]

Effects of casting thickness on microstructure, mechanical properties and abrasion resistance of Fe-B cast alloy have been systematically investigated. The results show that the microstructures of as-cast Fe-B alloy mainly consist of martensite, pearlite and M 2 B; with increasing of casting thickness, the V m / V p (where V p shows volume fraction of pearlite and V m shows volume fraction of martensite) decreases, while the morphology, composition and V b (volume fraction of boride) of Fe-B alloy are nearly unchanged. Moreover, with increasing of casting thickness, the microhardnesses of martensite, pearlite and M 2 B have little change, while the bulk hardness of as-cast Fe-B alloy decreases in a line relationship (y = −0.33x+64.67) owning to the decreasing of V m / V p . During wear process, the predominant wear mechanism of as-cast Fe-B alloy may change from microcutting to microploughing with decreasing V m / V p , resulting in the more and more boride being crushed by F ⊥ . As a result, the wear weight loss of Fe-B increases (i.e. the abrasion resistance decreases) with the decreasing of V m / V p , indicating that the V m / V p has positive influence on abrasion resistance of Fe-B cast alloy. [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]