To investigate the possibility of inoculating eutectic cells, a novel Al-10Si-2Fe master alloy was synthesized and tested in Sr-modifi ed A356 alloy. The new master alloy that consists of α-Al, Si and β-Al5FeSi phas...To investigate the possibility of inoculating eutectic cells, a novel Al-10Si-2Fe master alloy was synthesized and tested in Sr-modifi ed A356 alloy. The new master alloy that consists of α-Al, Si and β-Al5FeSi phases was prepared by a casting process, and the silicon phase was found to grow epitaxially from the β-Al5FeSi particles. The inoculation effi ciency of the new master alloy on Sr-modifi ed A356 alloy has been investigated by quenching experiment and thermal analysis. With the addition of the new master alloy, the area density of eutectic cells is effectively increased by 100% and the eutectic growth temperature is increased by 1.5 oC. Therefore, the new master alloy is deduced to introduce nucleating substrates for eutectic cells and to refi ne the eutectic cells in Sr-modifi ed A356 alloy. There is no poisonous interaction between the Al-10Si-2Fe master alloy and the Sr in this study. Consequently, the mechanical properties have been improved by the addition of the new master alloy.展开更多
The phosphide eutectic formation process in high purity Fe-4. 6% C alloy, in which 0.02%-1.0% P was added, was studied with DTA, SEM and EDS, and the effect of cerium on the morphology of phosphide eutectic in the te...The phosphide eutectic formation process in high purity Fe-4. 6% C alloy, in which 0.02%-1.0% P was added, was studied with DTA, SEM and EDS, and the effect of cerium on the morphology of phosphide eutectic in the ternary Fe-C-P alloy was also investigated. The results show that the ternary phosphide eutectic with the addition of 0.04% P is formed at low cooling rate. After cerium is added, the morphology of phosphide eutectic is changed from non-continuous or continuous distribution net to round or nodular form locating along the eutectic cell boundaries.展开更多
The thermal conductivity/diffusivity of pearlitic grey irons with various carbon contents was investigated by the laser flash method. The materials were cast in controlled thermal environments producing three dissimil...The thermal conductivity/diffusivity of pearlitic grey irons with various carbon contents was investigated by the laser flash method. The materials were cast in controlled thermal environments producing three dissimilar cooling rates. The cooling rates together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content, the carbon equivalent, and the fraction of the former primary solidified austenite transformed into pearlite. The results show that the optimal thermal transport properties are obtained at medium cooling rates. Equations are given for the thermal conductivity of pearlite, solidified as pre-eutectic austenite, and the eutectic of grey iron. The thermal conductivity of pearlitic grey iron is modelled at both room temperature and elevated temperatures with good accuracy.展开更多
基金supported by the National Natural Science Foundation of China(No.51371109)
文摘To investigate the possibility of inoculating eutectic cells, a novel Al-10Si-2Fe master alloy was synthesized and tested in Sr-modifi ed A356 alloy. The new master alloy that consists of α-Al, Si and β-Al5FeSi phases was prepared by a casting process, and the silicon phase was found to grow epitaxially from the β-Al5FeSi particles. The inoculation effi ciency of the new master alloy on Sr-modifi ed A356 alloy has been investigated by quenching experiment and thermal analysis. With the addition of the new master alloy, the area density of eutectic cells is effectively increased by 100% and the eutectic growth temperature is increased by 1.5 oC. Therefore, the new master alloy is deduced to introduce nucleating substrates for eutectic cells and to refi ne the eutectic cells in Sr-modifi ed A356 alloy. There is no poisonous interaction between the Al-10Si-2Fe master alloy and the Sr in this study. Consequently, the mechanical properties have been improved by the addition of the new master alloy.
文摘The phosphide eutectic formation process in high purity Fe-4. 6% C alloy, in which 0.02%-1.0% P was added, was studied with DTA, SEM and EDS, and the effect of cerium on the morphology of phosphide eutectic in the ternary Fe-C-P alloy was also investigated. The results show that the ternary phosphide eutectic with the addition of 0.04% P is formed at low cooling rate. After cerium is added, the morphology of phosphide eutectic is changed from non-continuous or continuous distribution net to round or nodular form locating along the eutectic cell boundaries.
文摘The thermal conductivity/diffusivity of pearlitic grey irons with various carbon contents was investigated by the laser flash method. The materials were cast in controlled thermal environments producing three dissimilar cooling rates. The cooling rates together with the carbon content largely influence the thermal conductivity of grey iron. Linear relationships exist between the thermal conductivity and the carbon content, the carbon equivalent, and the fraction of the former primary solidified austenite transformed into pearlite. The results show that the optimal thermal transport properties are obtained at medium cooling rates. Equations are given for the thermal conductivity of pearlite, solidified as pre-eutectic austenite, and the eutectic of grey iron. The thermal conductivity of pearlitic grey iron is modelled at both room temperature and elevated temperatures with good accuracy.
