| Aluminum bronze alloy is often used to manufacture high strength bearings,gear blanks,connecting rod bush,sealing ring and other mechanical parts because of the high hardness and good wear resistance.These parts often fail due to friction and wear,which causes great economic losses.Therefore,it is necessary to study and develop new processing methods and enhance wear resistance.QAl9-4 alloy was selected as the research objects in this study,and processed by multi-directional forging and aging coupling technology.The microstructure characteristics of alloy were observed by metallographic microscope,scanning electron microscope and transmission electron microscope.The tensile test at room temperature,dry sliding friction and two-body abrasive wear test were carried out on the alloy.The microstructure evolution and mechanical properties,the weight loss before and after wear,the surface worn morphology and roughness,the microstructure and the hardness change of the subsurface layer before and after wear were analyzed.The effect of microstructure,hardness,ductility,friction coefficient and work-hardening on the wear behavior of aluminum bronze alloy prepared by multi-directional forging and aging treatment was studied.The results show that the microstructure has been deformed seriously after multi-directional forging.Besides,there are a large number of ultrafine crystals,dislocation density,dislocation cells and twins in the microstructure.The strengthen mechanism mainly include the fine grain strengthening and dislocation strengthening.The multi-directional forging and aging made the aluminum bronze alloy obtain the ultrafine crystal structure with double peak size,and then the comprehensive mechanical properties are greatly improved.In dry sliding friction and wear,the strength and hardness of multi-directional forging sample were improved and the friction coefficient was reduced,but the wear resistance is reduced by 23%.The lower work hardening ability is the main factor leading to the low wear resistance.After multi-directional forging and aging treatment,although the friction coefficient is high,due to its high strength,hardness,good ductility and work hardening ability,the dry sliding wear resistance is improved by 57%.The wear resistance of aluminum bronze alloy is not improved by multi-directional forging or multi-directional forging and aging treatment during hard abrasive wear.This is mainly because the hardness of abrasive particles is much greater than that of materials,so the increase of material hardness has little influence on wear resistance.In two kinds of wear conditions,the main wear mechanism of the alloy is abrasive wear. |
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