Damage and plastic flow in a Al-Si-Cu thixocast alloy

Thixocast samples of an Al-Si-Cu alloy were solution treated at 500°C for 4 h, aged at 170°C for different times and tensile tested at room temperature. Statistical analysis on the fractured Si particles has pointed out how the fraction of damaged particles is influenced by the ageing treatments performed before deformation. The damage accumulation per unit of strain decreases with increasing ductility of the samples. The Considére criterion for plastic instability shows no significative necking.