The Research On Microstructure And Property Of Al-Cu Alloy By Semi-Solid Processing

The microstructures and mechanical properties of Al-Cu alloys fabricated by semi-solid squeezing casting processing(SSC) was studied in this paper. The microstrutures and mechanical properties of Al-10Cu alloys, Al-20Cu alloys and Al-40Cu alloys produced by the SSC were investigated by DSC, SEM, OM and tensile strength test. The refining mechanism of the microstructures was analysed in the processing. In addition, the pilot study about the wear resistance of Al-40Cu alloys was discussed.These researches indicate that the microstructures of Al-Cu alloys casting produced by SSC were improved; The mechanical properties of Al-Cu alloys at room temperature were increased. Better abrasive resistance at room temperature can also be obtained by the processing. So this technology has its advantages, and can be applied in some fields.The shape ofα-Al in Al-20Cu alloy fabricated by conventional casting was dendrite. When the alloy was prepared by SSC process, theα-Al in the alloys presented rosette or equiaxed shape. And the average size of theα-Al was approximately 50-80μm, which was obviously smaller than that of the Al-20Cu alloy made by conventional casting(200μm). The shape ofθI (CuAl2) in Al-40Cu alloys prepared by SSC casting was rounder than conventional casting. The average size in length was decreased from 500μm (conventional casting) to 80μm; The length-width ratio was reduced from 6 to 2.5.The homogeneity of temperature field and concentration field resulted from stirring in the process of SSC make undercooling zone of concentration and temperature gradient of the liquid reduced, thus the dendrites growthing are stunted, and the crystal grains in the Al-Cu alloys become equiaxed.The room temperature mechanical properties of the Al-Cu alloys prepared by SSC are improved very much; The Al-40Cu alloy produced by the SSC possessed lower wear rate. The wear mechanism of the Al-40Cu alloys mainly was adhesion and abrasion.