Study On Heat Treatment Process And Properties Of Aluminum Bronze (QAl10-4-4) Connecting Rod Bushing

Copper-based alloys,consisting of aluminum as the main alloying element,are called aluminum bronze.It has high strength and plasticity(higher than more than tin bronze),and has excellent chemical stability,more acid than tin bronze,alkali solution corrosion,especially the high corrosion resistance fatigue strength,in seawater and other liquids under repeated impact can not be easy to corrosion cracking,so it is widely used in industry.In this experiment,QAl10-4-4 aluminum bronze alloy was taken as the research object,and the performance of diesel bearing liner was used as the reference index(tensile strength650-750 MPa,yield strength ?460MPa,elongation ?10%).Through hardness test(HB-3000model),room temperature stretching(TLS-W50000 A model),Tensile fracture morphology analysis(SU-1500 model),XRD phase analysis(ALY-3700 model),Metallographic tissue Analysis(DM18/ MC190 HD model)and scanning microstructure analysis(SU5000 model)and other characterization methods the effects of different heat treatment processes on the microstructure and mechanical properties of the aluminum bronze alloy were studied,so as to determine the optimum heat treatment process of the alloy.The following results were obtained through experimental research:1)The optimum solidification treatment process of QAl10-4-4 aluminum bronze alloy after forging is 850?/2h,the hardness of the alloy at this temperature is 222 HB,the tensile strength is 750 MPa,the yield strength is 497 MPa,the elongation is 13.4%,and the high hardness and high strength of the forging alloy after solid dissolution and quenching,It comes from the comprehensive effect of ???' martensite transformation and solid dissolution enhancement during quenching.2)The internal stress formed inside the workpiece during solid dissolution treatmentcan be eliminated by aging treatment,so as to stabilize the microstructure and grain size of the alloy and improve the mechanical properties of the alloy.At 500 ? aging 1h,QAl10-4-4aluminum bronze alloy reached the maximum hardness of 240 HB,tensile strength of 732 MPa,yield strength of 542 MPa,but because at this time the alloy elongation is the lowest,only8.4%;in 650 ? aging 2h,The hardness of QAl10-4-4 aluminum bronze alloy is 210 HB,the tensile strength is 728 MPa,the yield strength is 493 MPa,and the elongation is 22.6%.650?/2H not only ensures a certain degree of toughness but also satisfies a certain shape.The treatment is mainly by the quenching state of the over-saturated solid solute ? and ?'martensite decomposition precipitation of the small granular K phase formation of the precipitation enhancement,to ensure the toughness of the alloy,aging treatment can also make the alloy to get a finer organization of the ? phase,greatly improve the plasticity of the alloy,so that the alloy has a high toughness and good plastic toughness.