The feasibility of semi solid processing of hypereutectic A390 alloys using a novel rheoforming process was investigated.A combination of the swirl enthalpy equilibration device (SEED) process, isothermal holding usin...The feasibility of semi solid processing of hypereutectic A390 alloys using a novel rheoforming process was investigated.A combination of the swirl enthalpy equilibration device (SEED) process, isothermal holding using insulation and addition of solid alloy during swirling was introduced as a novel method to improve the processability of semi solid slurry.The effects of isothermal holding and the addition of solid alloy on the temperature gradient between the centre and the wall and on the formation of α(Al) particles were examined.In additional tests, phosphorus and strontium were added to the molten metal to refine the primary and eutectic silicon structure to facilitate semi solid processing.The results show that the combination of the SEED process with two additional processing steps can produce semi-solid A390 alloys that can be rheoprocessed.The microstructure reveals an adequate amount of non-dendritic α(Al) globules surrounded by liquid, which greatly improves the processability of semi-solid slurry.展开更多
The development of a modified 206 alloy whose composition was optimized to minimize hot tearing during semi-solid forming was reported. The effect of varying silicon, copper and iron contents was investigated using a ...The development of a modified 206 alloy whose composition was optimized to minimize hot tearing during semi-solid forming was reported. The effect of varying silicon, copper and iron contents was investigated using a design of experiment (DOE) approach. Semi-solid slurries were prepared using the SEED process and injected into a high pressure die casting press. The hot tearing sensitivity results were reported for different alloy variants. The microstructure evolution during the semi-solid preparation was presented along with actual die cast components. The effects of silicon, copper and iron on mechanical properties in the T7 condition were also analyzed. Beyond the benefit of reducing hot tearing, it is shown that the tensile and fatigue properties remain compatible with the automotive industry requirements.展开更多
基金the financial support provided by the Natural Sciences and Engineering Research Council of Canada (NSERC) and Rio Tinto Alcan through the NSERC Industrial Research Chair in Metallurgy of Aluminum Transformation at Université du Québec à Chicoutimi
文摘The feasibility of semi solid processing of hypereutectic A390 alloys using a novel rheoforming process was investigated.A combination of the swirl enthalpy equilibration device (SEED) process, isothermal holding using insulation and addition of solid alloy during swirling was introduced as a novel method to improve the processability of semi solid slurry.The effects of isothermal holding and the addition of solid alloy on the temperature gradient between the centre and the wall and on the formation of α(Al) particles were examined.In additional tests, phosphorus and strontium were added to the molten metal to refine the primary and eutectic silicon structure to facilitate semi solid processing.The results show that the combination of the SEED process with two additional processing steps can produce semi-solid A390 alloys that can be rheoprocessed.The microstructure reveals an adequate amount of non-dendritic α(Al) globules surrounded by liquid, which greatly improves the processability of semi-solid slurry.
文摘The development of a modified 206 alloy whose composition was optimized to minimize hot tearing during semi-solid forming was reported. The effect of varying silicon, copper and iron contents was investigated using a design of experiment (DOE) approach. Semi-solid slurries were prepared using the SEED process and injected into a high pressure die casting press. The hot tearing sensitivity results were reported for different alloy variants. The microstructure evolution during the semi-solid preparation was presented along with actual die cast components. The effects of silicon, copper and iron on mechanical properties in the T7 condition were also analyzed. Beyond the benefit of reducing hot tearing, it is shown that the tensile and fatigue properties remain compatible with the automotive industry requirements.
