Study on the thermal expansion and thermal cycling of AlN_p/Al composites

The AlN particle reinforced aluminum matrix composite with 50% volume fraction was fabricated by the squeeze-casting technology. The thermal expansion behavior and its response to thermal cycling were studied between 20°C and 400°C. Compared with four theoretical models, the measured CTEs of the composite lie within the elastic bounds derived by Schapery's analysis. The analysis results of Schapery's model and Kerner's model agree well with the CTEs of the composite at lower temperature and elevated temperature, respectively. The strain hysteresis was observed between heating and cooling curves during cycling. This was attributed primarily to the inelastic behavior of the matrix induced by matrix residual stresses.