To assess the effect of silicon content (SC) and test parameters on the lubricated wear of Zn-30 wt.% Al-3 wt.% Cu-(0.5–5) wt.% Si alloys, six quaternary alloys were produced by casting. Their wear properties were investigated at different ranges of contact pressure (CP) of 1–8 MPa and sliding velocity (SV) of 1–3 ms⁻¹ for two different sliding distances (SD) of 20 km and 108 km. It was observed that Si addition (SA) improved the tribological properties of Zn-30Al-3Cu alloy, but an increase in the SC above a certain percentage (0.5%) adversely affected these properties. Therefore, Zn-30Al-3Cu-0.5Si alloy demonstrated the lowest friction coefficient (FC) and wear volume (WV) among the alloys tested. The correlations between the lubricated wear properties (FC and WV) of the alloys and test conditions (CP and SV) were made by non-linear regression analysis using the wear test data. Finally, the equations for the relationship between the wear properties of the alloys and the test parameters were determined.

In this study, the effect of boriding temperature and time on the structural and mechanical properties of M42 high speed steel were investigated. Samples placed in Ekabor II powder were exposed to pack boriding treatment at 900°C and 1000°C for 4 hour and at 950°C for 2, 4 and 6 hours. Scanning electron microscope (SEM) images indicate that boron diffuses into the samples and a sawtooth-like cross-sectional morphology is formed. The presence of boron has also been proven by Energy Dispersive X-ray spectrometry (EDX). In addition, it was determined that boron layer thickness increased with increasing boriding temperature. When the microhardness values were examined, it was observed that the sample borided at the highest temperature had the highest hardness value and the hardness values decrease with the decreasing of boriding temperature. Similar results were also obtained regarding the boriding time. The highest microhardness and layer thickness values were obtained after 6 hours of boriding. Additionally, it was observed that the hardness values of borided samples decreased as they moved from the surface to the inner parts.