Comparative study of microstructure and texture of cast and homogenized TX32 magnesium alloy after hot deformation

Abstract

The effect of homogenization on the hot deformation behavior and texture evolution of Mg-3Sn-2Ca (TX32) alloy is investigated. The cast-homogenized alloy samples were hot compressed in the temperature and strain rate ranges of 300–500 °C and 0.0003–10 s−1, respectively, and a processing map has been developed by using the flow stress data. The map revealed two dynamic recrystallization (DRX) domains with a peak efficiency of 44% at 360 °C/0.0003 s−1 (Domain 1) and 43% at 485 °C/0.1 s−1 (Domain 2). When compared with the map for as-cast condition, it is observed that both the domains moved towards higher temperatures although the shift of Domain 1 is more noticeable. The apparent activation energy values in the two domains and the regime of flow instability are nearly unchanged by homogenization, suggesting that Mg2Ca and CaMgSn particles in the microstructure are thermally stable. Specimens deformed under conditions in Domain 1 have high Schmid factors for {0001} $$\left\langle {11\bar 20} \right\rangle$$ basal slip and $$\left\{ {1\bar 100} \right\}$$ $$\left\langle {11\bar 20} \right\rangle$$ prismatic slip, while in Domain 2 the deformation progressed due to $$\left\{ {11\bar 2 \bar 2} \right\}$$ $$\left\langle {11\bar 2 \bar 3} \right\rangle$$ second-order pyramidal slip.