Thermal cycling behaviour of the magnesium alloy based hybrid composite in transverse direction

Abstract

The thermal cycling behaviour of a creep-resistant AE42 alloy reinforced with 20 vol% saffil short fibre as well as various volume fractions of saffil short fibre and SiC particulate has been examined in the transverse direction in the temperature range of 30–350 ◦C. For comparison, the thermal cycling behaviour of the unreinforced AE42 alloy is also examined. It is found that the linear instantaneous CTE curves of composites show a positive deviation from linearity above 215–230 ◦C, which is attributed to the release of residual compressive strain arising from the squeeze casting process. The experimentally obtained CTE of the composites is compared with the theoretically calculated values. The CTE of the hybrid composite is calculated by a linear subtraction of the expected decrease in CTE with the addition of SiC particulates from the CTE calculated for composite containing short fibres alone assuming a rule of mixture. However, it is observed that the fibres and particulates interact in a more complex manner and the decrease in CTE with the addition of particulates in a hybrid composite is greater than that obtained by the simple linear subtraction assuming a rule of mixture.