To improve the understanding of coupling effect between dynamic recrystallization(DRX)behaviors and flow behaviors of as-cast AlCu4 SiMg, a finite element(FE) simulation equipped with the models of DRX evolution was i...To improve the understanding of coupling effect between dynamic recrystallization(DRX)behaviors and flow behaviors of as-cast AlCu4 SiMg, a finite element(FE) simulation equipped with the models of DRX evolution was implemented. A series of isothermal compression tests were performed primarily on a Gleeble-3500 thermo-mechanical simulator in a temperature range of 648-748 K and a strain rate range of 0.01-10 s-1.According to the measured true stress-strain data,the strain hardening rate curves(dσ/dε versus σ) were plotted to identify the critical strains for DRX initiation(εc). By further derivation of the related material constants, the DRX volume fraction equation and the strain for 50% DRX(ε0.5) equation were solved. Accordingly, the aforementioned DRX equations were implanted into the FE model to conduct a series of simulations for the isothermal compression tests. The results show that during the evolution of DRX volume fraction at a fixed strain rate, the strain required for the same amount of DRX volume fraction increases with decreasing temperature. In contrast, at a fixed temperature, it increases with increasing strain rate. Ultimately, the DRX kinetics model of AlCu4 SiMg alloy and the consequence of the FE analysis were validated by microstructure observations.展开更多
Solidification processes of Al7SiMg-xY(0.1wt%,0.3wt%,0.5wt%) alloys were investigated by thermal analysis.The microstructures were observed by using optical microscopy and scanning electron microscopy.Effects of diffe...Solidification processes of Al7SiMg-xY(0.1wt%,0.3wt%,0.5wt%) alloys were investigated by thermal analysis.The microstructures were observed by using optical microscopy and scanning electron microscopy.Effects of different concentrations of yttrium on tensile performance both as cast and T6 heat treated were studied at room temperature,respectively.The results show that little changes happen in liquidus with increases concentration of yttrium.While it results in obvious depression of solidus and eutectic arrest temperature in solidification process.Moreover,the solidification range increases significantly.The performance is better when concentration of yttrium is 0.1wt%.With increment of yttrium,more large flake-like compounds of yttrium gather in grain boundaries,performance especially the elongation of the alloy decrease remarkably.展开更多
基金Project(cstc2016jcyjA0335)supported by Chongqing Foundation and Frontier Research,ChinaProject(P2017-020)supported by Open Fund Project of State Key Laboratory of Materials Processing and Die&Mould Technology,China
文摘To improve the understanding of coupling effect between dynamic recrystallization(DRX)behaviors and flow behaviors of as-cast AlCu4 SiMg, a finite element(FE) simulation equipped with the models of DRX evolution was implemented. A series of isothermal compression tests were performed primarily on a Gleeble-3500 thermo-mechanical simulator in a temperature range of 648-748 K and a strain rate range of 0.01-10 s-1.According to the measured true stress-strain data,the strain hardening rate curves(dσ/dε versus σ) were plotted to identify the critical strains for DRX initiation(εc). By further derivation of the related material constants, the DRX volume fraction equation and the strain for 50% DRX(ε0.5) equation were solved. Accordingly, the aforementioned DRX equations were implanted into the FE model to conduct a series of simulations for the isothermal compression tests. The results show that during the evolution of DRX volume fraction at a fixed strain rate, the strain required for the same amount of DRX volume fraction increases with decreasing temperature. In contrast, at a fixed temperature, it increases with increasing strain rate. Ultimately, the DRX kinetics model of AlCu4 SiMg alloy and the consequence of the FE analysis were validated by microstructure observations.
文摘Solidification processes of Al7SiMg-xY(0.1wt%,0.3wt%,0.5wt%) alloys were investigated by thermal analysis.The microstructures were observed by using optical microscopy and scanning electron microscopy.Effects of different concentrations of yttrium on tensile performance both as cast and T6 heat treated were studied at room temperature,respectively.The results show that little changes happen in liquidus with increases concentration of yttrium.While it results in obvious depression of solidus and eutectic arrest temperature in solidification process.Moreover,the solidification range increases significantly.The performance is better when concentration of yttrium is 0.1wt%.With increment of yttrium,more large flake-like compounds of yttrium gather in grain boundaries,performance especially the elongation of the alloy decrease remarkably.
