Synthesis Optimization Of Microstructure And Mechanical Property In Aluminum Bronze Die Material

Aluminum bronze is suitable for die material because it has good casting characteristics, excellent strength, hardness and wear resistance. Compared to the alloy steel die material, aluminum bronze has better thermal conductivity, and also not easily has the attrition with ferrous metals, and compared to beryllium bronze, aluminum bronze is of low cost and non-toxic, so it is a valuable promotional die material. But the wear resistance cannot meet the requirements of engineering under heave load, it leads to the die life short. In order to increase the mechanical property of the designed alloy Cu-12.5Al-4Fe-1Co-0.5Ni, the paper uses the optic microscope, hardness tester, XRD,SEM and mechanical property testing equipments to research the effect of the grain refiners and alloy element on the microstructures and properties by changing the content of Mn and adding different grain refiners. And on the basis, the solution and aging processes of the alloy are studied to improve the mechanical property.The research shows that the cast microstructures consist of β’ phase, γ2 +α phase and κ phase. With the increase of the content of Mn, the electrical conductivity decreases,and the inhibition of the β’ phase’s eutectoid decomposition is enhanced,the content of β’ phase gradually increases and the content of α phase decreases, alloy hardness increases accordingly. This experiment determined 2%Mn as the best quantity considering the thermal conductivity and mechanical property of the alloy.Adding Cu-10 RE and Al-3B alone can effectively refine the alloy grain, thus the mechanical properties of the alloy are improved, but the performance of the rare earth is better. The hardness of the alloy reaches the maximum with union addition of Cu-10 RE and Al-3B.After solution, the matrix β’ phase increases and shows martensite morphology.Under 980℃ solution, the grain of the alloy coarsens and the performances decrease.Martensitic characteristics of β’ phase disappears gradually, κ phase becomes thick,petal-shaped with the increase of aging temperature. The best heat treatment process of this study is 950℃× 3h solution and 500℃×2h aging. The wear of the alloy specimen under the best heat treatment process is 32% less than that of as-cast.