中国有色金属学会会刊（英文版）
中國有色金屬學會會刊（英文版）
중국유색금속학회회간（영문판）
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
2007年
3期
509-513
,共5页
Al-Si alloy%microstructure%secondary particle size%superplasticity%grain size%metals and alloys
Three kinds of Al-11%Si (mass fraction) alloy samples with different processes were produced to investigate the effect of microstructures on its superplasticity. Among them, the as-ECAP sample pressed 16 passes has ultrafine grains (300 nm) and the finest secondary particles. The ECAP-T6 sample, with ECAP 16 passes followed by T6 treatment, has fine secondary particles (3 μm) but the largest grains (8 μm). Contrarily, the T6-ECAP sample, with T6 treatment followed by ECAP 16 passes, has ultrafine grains and the large secondary particles (7 μm). The tensile testing results show that the as-ECAP sample exhibits superplasticity at high strain rate of 5.75×10-1 s-1 due to its fine secondary particles and ultrafine grains. The ECAP-T6 sample, however, does not exhibit superplasticity at the same high strain rate of 5.75×10-1 s-1 because it has relatively large secondary particles and large grains. Remarkably, the T6-ECAP sample does not have superplasticity even at the lower strain rate of 1.15×10-1 s-1, attributing to its comparatively large secondary particles. When most secondary particles are larger than 7μm, the high strain rate superplasticity could not be obtained even if this sample has ultrafine grains.
