Heat treatment effect on microstructure, mechanical properties and fracture behavior of cylinder head aluminum-silicon-copper alloy

In the present article, T4 and T6 heat treatments carried out to improve microstructure and mechanical properties (hardness and tensile) of Al-Si-Cu alloys (A380 alloy, which has been used in engine cylinder heads). For this purpose, solution annealing was performed at 490 ºC for 5 h. The T6 aging was executed at 180, 200, 220, 240 ºC for 1, 3, 5, 7 h. Hardness experimental results showed that optimum values for the T6 aging temperature and time are generally 200˚C and 3 h, respectively, as the hardness increased. Evaluation of the microstructures and fractured surfaces were performed with optical and scanning electron microscopes. After T6 treatment, tensile strength increased from 245 to 255 MPa and hardness from 88 to 95 Vickers. By applying T6 process in optimized tempeIn current paper two different regimes of heat treatments, namely T4 and T6 treatments of Al-Si-Cu alloy used in engine cylinder head were investigated and the effects and significance of time and temperature on microstructure and mechanical properties of the material were studied and compared. For this purpose, solution annealing was performed at 490 ºC for 5 h. The T6 aging was executed at 180, 200, 220, 240 ºC for 1, 3, 5, 7 h. Hardness testing results revealed that the optimum hardness is obtained for T6 at 200˚C and 3h, respectively, as the hardness increased. Evaluation of the microstructures and fractured surfaces were performed with optical and scanning electron microscopes. After T6 treatment, tensile strength increased from 245 to 255 MPa and hardness from 88 to 95 Vickers. By applying T6 process in optimized temperature and time, the hardness and tensile strengths of Al-Si-Cu alloy was enhanced from 10.5% compared to that of the T4 processes. The sensitivity analysis indicated that effect of the aging temperature is more significant in comparison to other parameters.
rature and time, the hardness and tensile strengths of Al-Si-Cu alloy was enhanced from 10.5% compared to that of the T4 processes. The sensitivity analysis indicated that effects of the aging temperature are more significant in comparison to other parameters