【摘要】 为获得性能优良的高硅铝合金材料,采用近液相线铸造法制备高硅铝合金坯料,并对坯料显微组织进行金相观察;采用M256-60428金相检验软件计算晶粒尺寸及其圆整度,研究浇注温度对高硅铝合金初生α(Al)相尺寸形貌和力学性能的影响,并采用JSM6490/LV扫描电镜扫描压缩试样断口。结果表明,随着浇注温度的降低,铝合金显微组织呈现由树枝晶向蔷薇状形态、再到球状或粒状组织变化;而后,随着合金熔体处于半固态区间时间的延长,铝合金中的初生α(Al)又开始出现合并长大,圆整度有了明显的改善。随着浇注温度的降低,试样的硬度值也在减小,且减小的梯度不断增大。试样在720℃温度下浇注的抗压强度约为620MPa,得到的高硅铝合金试样在压缩时发生解理断裂;而在605℃温度下浇注的抗压强度则为505MPa,浇注后试样发生了混合断裂。更多还原

【Abstract】 To get high-silicon Aluminum alloy with good quality,the billets were prepared by using near-liquidus casting technology.The microstructure of billets was observed by metalloscopy.The grain size and roundness degree were calculated by M256-60428 software.The influence of pouring temperature on the shape,size and mechanical property of high-silicon Aluminum alloy were studied.The fracture morphology of compressive sample was scanned by JSM6490/LV SEM.The results show that with decrease of pouring temperature,the microstructure of Aluminum alloy change from dendrite to rose and then to grain style.With the prolonging of holding time for the melting body of the alloy under semi-solid state,the primary α(Al) in the alloy again combine and grow up,and its roundness improved significantly.The hardness of the sample decreases with the decrease of pouring temperature,and the slope of decreasing getting steeper and steeper.Compression strength falls off from 620MPa to 505MPa with pouring temperature decreases from 720℃ to 605℃.The fracture morphology changes from cleavage fracture poured at 720℃ to ductile fracture poured at 620℃.更多还原