Aging behavior of Al_2O_3 short fiber reinforced Al-Cu alloy composites

摘要

Al_2O_3 short fiber reinforced Al-Cu composites containing 1%, 3%, 5% and 7% Cu were fabricated by a squeeze casting technique. The as-cast Al_2O_3/Al-Cu composites were solution treated at 535℃ and then aged at 170, 190 and 210℃, respectively. Age hardening behavior of the Al_2O_3/Al-Cu composites was analyzed by measuring the hardness of the samples at different aging temperatures and aging time. Microstmctures of the composites were observed by transmission electron microscope(TEM). The results indicate that the hardness of the Al_2O_3/ Al-Cu composites containing 7% Cu is much higher than that containing l%-5% Cu because of the large amount of CuAl_2 precipitant in the Al_2O_3/Al-Cu composite. With the increase of Cu content from 1% to 7%, the time needed for the appearance of peak hardness shortened, indicating that the addition of Cu can accelerate the kinetic of CuAl_2 precipitation in the Al_2O_3/ Al-Cu composites. The Al_2O_3/Al-Cu composite containing 7% Cu shows the highest increment of hardness by aging treatment. Therefore, in order to get a higher peak hardness, the Al_2O_3/Al-Cu composites need more Cu addition as compared with the un-reinforced Al-Cu alloys.