Dong Tianshun

Influence of Rapid Solidification of Cu-P Intermediate Alloy on Wear Resistance of Al-Si alloy

Abstract The influence of rapid solidification of Cu-P intermediate alloy on the wear resistance of Al-Si alloy is studied. TEM analysis indicates that at the cooling speed of 105-106 °C/s, the microstructure of melt-spin Cu-P ribbon consists of nano-grains and a little amount of amorphous areas, and the grain size of Cu3P in Cu-P intermediate alloy is decreased from 5-40 μm to 30-50 nm. Results show that the wear resistance of Al-Si alloy modified by melt-spin intermediate alloy are better than that of Al-Si alloy modified by massive ones; wear rate is decreased from 0.86% to 0.39%. Therefore, melt-spin treatment of Cu-P intermediate alloy is effective to improve the wear resistance of Al-Si alloy.

Microstructure and Wear Resistance of FeCrBSi Plasma-Sprayed Coating Remelted by Gas Tungsten Arc Welding Process

Herein, an FeCrBSi coating was fabricated via plasma spray on AISI1045 steel, and subsequently, a gas tungsten arc welding (GTA) process was employed to remelt the coating. The microstructure, microhardness, fracture toughness and surface roughness of the coating before and after remelting were investigated, as well as the wear resistance was tested by a UMT-3-type sliding wear apparatus. The results showed that, upon remelting, most defects in the as-sprayed coating were effectively eliminated, the surface roughness decreased by 43%, and the coating–substrate interface bonding changed from mechanical to metallurgical. The phase composition of the as-sprayed coating was primarily α-Fe and a small amount of hard Fe3B phase, while the remelted coating consisted of α-Fe and (Fe,Cr)23C6 and a small quantity of CrB. In addition, remelting the coating was found to induce a 287.6% increase in the fracture toughness, a 33.4% increase in the average microhardness, and a 47.5% decrease in the wear volume, while the failure mechanism changed from abrasive wear to fatigue wear upon remelting. Therefore, GTA remelting of plasma-sprayed coating was found to be a feasible method to obtain a coating with good wear resistance.