In-situ TEM study on the effect of stacking faults on micro-plasticity and proportional limit in SiC/Al composites

Enhancing the proportional limit of Al matrix composites (AMCs) is critical to the reliability of precision electronic instruments. In this paper, SiC/Al composites containing stacking faults (SFs) were successfully fabricated using pressure infiltration method. The proportional limit (σ_p5 and σ_p100) of SiC/Al composites with SFs reached 65 MPa and 124 MPa, respectively, which was 8%–22% higher than theoretical prediction of the Brown-Lukens empirical formula. In-situ TEM tensile test was conducted to reveal the strengthening behavior of SFs during micro-plasticity. The results showed that the extra strengthening effect in SiC/Al composites with SFs includes elastic interactions of SF extension, sessile stair-rod partial dislocations and interactions of SF networks and dislocation arrays. This work reveals the influence of SFs on the micro-plasticity and strengthening behavior of AMCs and proposes a new strategy to endow AMCs with higher proportional limit for precision instrumentation applications.