粉末液相模锻法制备BN增强Al-Cu基复合材料

Fabrication of Al-Cu Composite Reinforced with BN by Powder Liquid-Phase Forging

采用粉末液相模锻技术制备出近全致密Al-5.3%Cu-3.0%h-BN(质量分数,下同)复合材料,研究了该技术制备的复合材料的致密化及界面结合状况。采用SEM、XRD、TEM等分析手段对球磨前后粉末形貌、复合材料显微结构及物相组成进行表征,利用布氏硬度计对复合材料硬度进行测试。结果表明:在大量液相存在的情况下,施加外力可有效促进复合材料的致密化。粗铝粉(35μm)制备的复合材料晶粒呈细条状,具有方向性,T6热处理后发生原位再结晶;细铝粉(2μm)制备的复合材料晶粒细小,晶粒形貌不明显。复合材料界面由Al/Al2O3/BN组成,清晰可见,结合紧密。复合材料与基体合金相比,硬度提高近15%,细铝粉制备的复合材料硬度比粗铝粉略高。

Al-5.3wt%Cu composite reinforced with 3.0wt% h-BN with nearly full densification was fabricated by the process of liquid-phase forging. The powder morphology and comparative structural characteristics were analyzed using X-ray diffraction, scanning and transmission electron microscopy, and the composite hardness was measured by Brinell tester. Special attention was paid to the effects of the technique on the densification and the interface bonding of as-forged composites. Results reveal that the composite densification can be promoted effectively with plenty of embedded liquid phase under pressure. The composites fabricated using aluminium powder with different granularity show different grain characteristics, and in situ recrystallization occurs inside the original grains of 35 μm aluminium powder. Moreover, a good interface consisting of Al/Al2O3/BN is apparent in the composite. Compared with the basis alloy, the composite hardness increases nearly by 15%, and the composite with 2 μm aluminium powder shows better performance.