Abstract: Effects of forging and heat treatment on microstructure and mechanical properties of Al-7Si-1.6Cu alloy were investigated by means of mechanics performance test, OM, SEM and TEM observations. Results showed that by homogenization proces-sing(500 ℃,8 h), forging(forging temperature from 380 ℃ to 450 ℃, strain rate 60-90 s-1, pass compression ratio 10%-20%) and heat treatment(solid solution at 480 ℃ for 2 h,70 ℃ water-quenching,aging at 180 ℃ for 6 h), the hardness,tensile strength and elongation of the alloy increased by 18%,52% and 54.5% compared with the as-cast. Multidirectional forging process accelerated the breaking and spheroidizing of the eutectic Si particles. The precipitation of nanoscale second phase in the aging process had strengthening effect to the alloy. From the point of the dislocation density, the article explained the reasons for strength improvement by for-ging process.Zener-Hollomon parameters were adopted to illustrate the relationship of the forging process flow stress between defor-mation temperature and deformation rate.
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2017, Vol. 31 
