The effect of loading on the rupture structure of Al-Si alloys at elevated temperature

Two Al-Si alloys of different silicon content having 10 and 15 wt.% were tested by loading at an isothermal temperature of 540 °C. To explore the characteristics of the rupture structure, various loads (2-80 N) were chosen in this study. The results indicate that the rupture structures are mainly affected by transformation stress under lower load. Besides, the dissolved silicon is trended to distribute along α-Al dendrite boundary, but it is gradually governed by the increased loading-effect and restrain the distribution of eutectic silicon. Based on the both interactions, the two changing curves of rupture time reveal commonly a trend of that initial decrease and then increase, whereas the TR-value of 15 Si is larger than 10 Si. To increase the load will raise generally the hardness of rupture. However, this hardness of 10 Si is higher under 15 N-loaded below. The cracking paths were more preferred to proceed along the silicon particles clustered zone.