【摘 要】
：
Amorphous Al2O3-reinforced Al composite (am-Al2O3/Al) compacted from ultrafine Al powders for high-temperature usages confronts with drawbacks because crystallization of am-Al2O3 at high temperatures will result in serious strength loss.Aiming at this uns
【机 构】
：
Shenyang National Laboratory for Materials Science,Institute of Metal Research, Chinese Academy of S
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Amorphous Al2O3-reinforced Al composite (am-Al2O3/Al) compacted from ultrafine Al powders for high-temperature usages confronts with drawbacks because crystallization of am-Al2O3 at high temperatures will result in serious strength loss.Aiming at this unsolved problem,in this study,high-temperature Al materials with enhanced thermal stability were developed through introducing more thermally stable nano-sized particles via high-temperature pre-treatment of ultrafine Al powders.It was found that the pre-treatment at≤ 550 ℃ could introduce a few Al2O3 in the Al matrix and increase the strength of the composites,but the strength was still below that of am-Al2O3/Al because without being pinned firmly,grain boundaries (GBs) were softened at high temperature and intergranular fracture happened.When the pre-treatment was carried out at 600 ℃,nitridation and oxidation processes happened simultaneously,producing large numbers of intergranular (A1N + γ-A12O3) particles.GB sliding and intergranular fracture were suppressed;therefore,higher strength than that of am-Al2O3/Al was realized.Furthermore,the (AlN + γ-Ai2O3)/Al exhibited more superior thermal stability compared to amAl2O3/Al for annealing treatment at 580 ℃ for 8 h.Therefore,an effective way to fabricate high-temperature Al composite with enhanced thermal stability was developed in this study.
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