Recently, the consumption of aluminum alloys for weight reduction of automobile has been increased in order to improve fuel efficiency and to meet environmental regulations. Specifically, A356 alloy, one of the Al-Si-Mg casting alloys, has been widely used for automobile parts due to high strength a...
Recently, the consumption of aluminum alloys for weight reduction of automobile has been increased in order to improve fuel efficiency and to meet environmental regulations. Specifically, A356 alloy, one of the Al-Si-Mg casting alloys, has been widely used for automobile parts due to high strength and corrosion resistance, and excellent deformability.
Mass productions of A356 automobile parts are based on various casting processes such as gravity die casting, low pressure die casting, and counter pressure die casting. Especially, counter pressure die casting process pressurizes both the lower chamber containing molten aluminum and the upper chamber with metal molds so as to fill the mold under higher pressure than atmospheric pressure, resulting refinement of solidified microstructure, prevention of shrinkage defects, enhancement of mechanical properties.
Meanwhile, A356 alloy castings are generally followed by heat treatment process in order to improve mechanical properties. Most widely used heat treatment process for A356 alloy is so-called T6 heat treatment process which consists of solution heat treatment and subsequent artificial aging treatment. The optimal conditions for T6 heat treatment of A356 alloy have been extensively investigated experimentally but the results are limited to the gravity or low pressure die cast. If the aluminum cast has finer microstructure than those conventional casting methods (such as counter pressure casts), the optimal heat treatment condition for those cast should be determined either by experimental verification of the reported one from literatures or by new investigation with a series of heat treatment experiments.
When it comes to the optimization issue of heat treatment condition, it is the typical method to conduct a number of heat treatment experiments at different time and temperature conditions, followed by microstructure observation and mechanical test. This experimental approach, however, is time-consuming and expensive routines. Therefore, it is efficient to utilize numerical simulation techniques including yield strength modeling based on precipitation kinetics, and statistical approaches based on machine learning for optimization of heat treatment process.
In the present study, experimental investigations on microstructure and mechanical property of conter pressure cast A356 aluminum alloy under T5 (artificial aging only after casting) were conducted with a number of heat treatments under the temperature range of 160 to 200°C for 6 to 9 hours. Also, a yield strength model was developed based on the precipitation kinetics of which is experimentally confirmed in the present study and the optimal T5 heat condition was determined from the model calculations.
Recently, the consumption of aluminum alloys for weight reduction of automobile has been increased in order to improve fuel efficiency and to meet environmental regulations. Specifically, A356 alloy, one of the Al-Si-Mg casting alloys, has been widely used for automobile parts due to high strength and corrosion resistance, and excellent deformability.
Mass productions of A356 automobile parts are based on various casting processes such as gravity die casting, low pressure die casting, and counter pressure die casting. Especially, counter pressure die casting process pressurizes both the lower chamber containing molten aluminum and the upper chamber with metal molds so as to fill the mold under higher pressure than atmospheric pressure, resulting refinement of solidified microstructure, prevention of shrinkage defects, enhancement of mechanical properties.
Meanwhile, A356 alloy castings are generally followed by heat treatment process in order to improve mechanical properties. Most widely used heat treatment process for A356 alloy is so-called T6 heat treatment process which consists of solution heat treatment and subsequent artificial aging treatment. The optimal conditions for T6 heat treatment of A356 alloy have been extensively investigated experimentally but the results are limited to the gravity or low pressure die cast. If the aluminum cast has finer microstructure than those conventional casting methods (such as counter pressure casts), the optimal heat treatment condition for those cast should be determined either by experimental verification of the reported one from literatures or by new investigation with a series of heat treatment experiments.
When it comes to the optimization issue of heat treatment condition, it is the typical method to conduct a number of heat treatment experiments at different time and temperature conditions, followed by microstructure observation and mechanical test. This experimental approach, however, is time-consuming and expensive routines. Therefore, it is efficient to utilize numerical simulation techniques including yield strength modeling based on precipitation kinetics, and statistical approaches based on machine learning for optimization of heat treatment process.
In the present study, experimental investigations on microstructure and mechanical property of conter pressure cast A356 aluminum alloy under T5 (artificial aging only after casting) were conducted with a number of heat treatments under the temperature range of 160 to 200°C for 6 to 9 hours. Also, a yield strength model was developed based on the precipitation kinetics of which is experimentally confirmed in the present study and the optimal T5 heat condition was determined from the model calculations.
주제어
#A356 alloy Microstructure T5 heat treatment Yield strength Numerical simulation
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