Steady-state corrosion and wear behaviors of two Al-bronzes,Cu-14Al-X and QAl9-4,in 5.0% H2SO4 solution were investigated. It is found that wear loss of bronzes in 5.0% H2SO4 solution is lower than that in water or in air,namely,it exhibits negative synergy between corrosion and wear. Further analysis shows that corrosive solution plays an important role in cooling of specimen during the sliding wear to prevent the reduction of the surface hardness of specimen,induced by frictional heat. On the other hand,the bronzes suffer a de-alloying corrosion,and a noble copper subsurface and patina form on the specimen surface in corrosive solution,which has a passive function for further corrosion. The noble copper subsurface experiences strain hardening during the corrosion and wear,resulting in the increase of the surface hardness thus the increase in wear resistance.
Cu-14Al-4.5Fe bronze powders with and without 0.6% Ce were prepared and their coatings were fabricated on 45# carbon steel substrate by atmospheric plasma spraying. The effects of rare earth Ce on the coating interface bonding strength, coatings and bonding interface vertical sections microstructure were investigated by tensile machine, X-ray diffraction analysis, scanning electron microscopy (SEM) and electronic probe microanalysis (EPMA). The results showed that the shape of powders was more spherical like, and the coating's hardness and interface bonging tensile strength would be improved to 8.9% and 17.4%, respectively, higher than that of the Cu-14Al-4.5Fe coating without 0.6% Ce added. The refined of κ phases, well distributed matrix phases in coatings and the promotion of Fe, Al elements diffusion led to the improvement in interface bonding strength and hardness of the Cu-14Al-4.5Fe coating with addition of 0.6% Ce, which hardened and strengthened the coating.
A phase-field model(PFM)coupling with phase field,flow field and diffuse equation is presented for simulating isothermal dendrite growth of a nickel-copper alloy under a forced flow.Based on the finite difference method with uniform grid,the C programming code is implemented to complete the phase-field simulations.The simulation results indicate that the interfacial morphology,the symmetry of dendrite formation,the tip growth velocity and the concentration distribution are strongly influenced by the fluid flow.
