摘要
30-50 wt.%graphite nanoflakes(GNFs)/6061Al matrix composites were fabricated via spark plasma sintering(SPS)at 610℃.The effects of the sintering pressure and GNF content on the microstructure and properties of the composites were investigated.The results indicated that interfacial reactions were inhibited during SPS because no Al4C3 was detected.Moreover,the agglomeration of the GNFs increased,and the distribution orientation of the GNFs decreased with increasing the GNF content.The relative density,bending strength,and coefficient of thermal expansion(CTE)of the composites decreased,while the thermal conductivity(TC)in the X−Y direction increased.As the sintering pressure increased,the GNFs deagglomerated and were distributed preferentially in the X−Y direction,which increased the relative density,bending strength and TC,and decreased the CTE of the composites.The 50wt.%GNFs/6061Al matrix composite sintered at 610℃ under 55 MPa demonstrated the best performance,i.e.,bending strength of 72 MPa,TC and CTE(RT−100℃)of 254 W/(m·K)and 8.5×10^(−6)K^(−1)in the X−Y direction,and 55 W/(m·K)and 9.7×10^(−6)K^(−1)in the Z direction,respectively.
采用放电等离子体烧结(SPS)工艺在610℃制备30%~50%(质量分数)纳米石墨片(GNF)/6061Al基复合材料,研究烧结压力及GNF含量对复合材料显微组织和力学、热学性能的影响。结果表明,SPS有效抑制GNFs/6061Al基复合材料中Al4C3等界面反应产物的生成。随着GNF含量的增加,GNFs团聚程度增加,取向分布程度降低,复合材料致密度、抗弯强度及热膨胀系数(CTE)下降,X−Y方向热导率(TC)增大。提高烧结压力,有助于降低GNFs团聚程度,GNFs沿X−Y方向择优分布越明显,复合材料致密度、抗弯强度及TC增大,CTE下降。在610℃、55 MPa下烧结的50%GNFs/6061Al基复合材料的性能最佳,抗弯强度为72 MPa,TC及CTE分别为254 W/(m·K)和8.5×10^(−6) K^(−1)(室温~100℃,X−Y方向),以及55 W/(m·K)和9.7×10^(−6) K^(−1)(Z方向)。
基金
financial support from the International Science&Technology Cooperation Program of China(No.2014DFA50860)。
