The microstructures and tensile properties of semi-solid metal high pressure die cast(SSM-HPDC) F357 alloys with low and high levels of Fe,Ni and Cr were compared in different temper conditions.ThermoCalc software was...The microstructures and tensile properties of semi-solid metal high pressure die cast(SSM-HPDC) F357 alloys with low and high levels of Fe,Ni and Cr were compared in different temper conditions.ThermoCalc software was used to predict the different intermetallics that can be expected in the alloys,and scanning electron microscopy(SEM) with energy dispersive spectroscopy(EDS) was used to investigate the actual intermetallics that formed.The influence of these intermetallics on tensile properties was quantified.The results show that lower strength is obtained in the alloy with high Fe,Ni and Cr levels.This is attributed mainly to the formation of more π-Al8FeMg3Si6 phase,which removes strengthening Mg atoms from solid solution.Also,the ductility of the high Fe,Ni and Cr levels alloy is decreased significantly due to microcracking of the higher volume fraction π-Al8FeMg3Si6 and Al9FeNi phases.The combination of lower strength and ductility results in a decrease of the quality index of this alloy compared with the alloy with low levels of Fe,Ni and Cr.展开更多
The corrosion behavior(in chloride medium) of the surface layer of SSM-HPDC plates of alloys 7075-T6 and 2024-T6 was compared with that of the wrought alloys 7075-T6 and 2024-T6.Potentiodynamic testing was performed i...The corrosion behavior(in chloride medium) of the surface layer of SSM-HPDC plates of alloys 7075-T6 and 2024-T6 was compared with that of the wrought alloys 7075-T6 and 2024-T6.Potentiodynamic testing was performed in deaerated 3.5%NaCl solution.In separate tests,the open-circuit potential was monitored in aerated 3.5% NaCl for 30 min after immersion.The electrochemical tests show that there is no significant difference in the pitting potential of the wrought alloys and that of the Cu-enriched surfaces of the SSM-HPDC alloys.展开更多
文摘The microstructures and tensile properties of semi-solid metal high pressure die cast(SSM-HPDC) F357 alloys with low and high levels of Fe,Ni and Cr were compared in different temper conditions.ThermoCalc software was used to predict the different intermetallics that can be expected in the alloys,and scanning electron microscopy(SEM) with energy dispersive spectroscopy(EDS) was used to investigate the actual intermetallics that formed.The influence of these intermetallics on tensile properties was quantified.The results show that lower strength is obtained in the alloy with high Fe,Ni and Cr levels.This is attributed mainly to the formation of more π-Al8FeMg3Si6 phase,which removes strengthening Mg atoms from solid solution.Also,the ductility of the high Fe,Ni and Cr levels alloy is decreased significantly due to microcracking of the higher volume fraction π-Al8FeMg3Si6 and Al9FeNi phases.The combination of lower strength and ductility results in a decrease of the quality index of this alloy compared with the alloy with low levels of Fe,Ni and Cr.
文摘The corrosion behavior(in chloride medium) of the surface layer of SSM-HPDC plates of alloys 7075-T6 and 2024-T6 was compared with that of the wrought alloys 7075-T6 and 2024-T6.Potentiodynamic testing was performed in deaerated 3.5%NaCl solution.In separate tests,the open-circuit potential was monitored in aerated 3.5% NaCl for 30 min after immersion.The electrochemical tests show that there is no significant difference in the pitting potential of the wrought alloys and that of the Cu-enriched surfaces of the SSM-HPDC alloys.
