Influence of solidification parameters on the thermal conductivity of cast A319 aluminum alloy

One of the major causes of premature failure in A319 aluminum alloy powertrain components is the accumulation of thermal stresses. Consequently, the engine operating temperature is restricted to prevent large internal temperature gradients in the components, thereby reducing thermal efficiency. The objective of this research was to investigate the influence of solidification parameters on the thermal conductivity of A319 alloy, in an effort to promote uniform temperature distributions in powertrain components. Castings with varying mould preheating temperatures were characterized using thermal analysis, microstructural analysis, mechanical testing, and thermal conductivity measurements via the transient plane source method. The results indicated that increasing solidification rate was associated with two competing phenomena: Whereas finer secondary phases improved conductivity, a finer dendritic structure reduced conductivity. As a result, a critical solidification rate was found to attain maximum thermal conductivity in A319.

Influence of solidification parameters on the thermal conductivity of cast A319 aluminum alloy

One of the major causes of premature failure in A319 aluminum alloy powertrain components is the accumulation of thermal stresses. Consequently, the engine operating temperature is restricted to prevent large internal temperature gradients in the components, thereby reducing thermal efficiency. The objective of this research was to investigate the influence of solidification parameters on the thermal conductivity of A319 alloy, in an effort to promote uniform temperature distributions in powertrain components. Castings with varying mould preheating temperatures were characterized using thermal analysis, microstructural analysis, mechanical testing, and thermal conductivity measurements via the transient plane source method. The results indicated that increasing solidification rate was associated with two competing phenomena: Whereas finer secondary phases improved conductivity, a finer dendritic structure reduced conductivity. As a result, a critical solidification rate was found to attain maximum thermal conductivity in A319.

Effect of Pouring Temperature on Mechanical Properties of Semisolid Cast A319 Aluminum Alloy

Semisolid metal (SSM) casting or thixoforming is a technique used to produce near net-shaped products. The process is used with non-ferrous metals, such as aluminium, copper and magnesium. Furthermore, it has advantage over conventional casting due to suppression of dendrite growth. In the present work, the semisolid casting of A319 aluminium alloy has been carried out by using an inclined plate with different melt pouring temperatures (620, 625, 630 and 635 °C). A319 alloy melt undergoes partial solidification when it flows down on an inclined plate. It results in continuous formation of columnar dendrites on plate wall. Due to forced convection, these dendrites are sheared off into equiaxed or fragmented grains and then washed away continuously to produce semisolid slurry at plate exit. The prepared castings were checked for their mechanical properties like tensile, hardness and impact strength. The results obtained were compared with that of alloy prepared from conventional sand casting. It was found that there is an enhancement in mechanical properties due to shearing off columnar dendrites.