原位自生Al18B4O33w/6061复合材料的组织、硬度及耐磨性能

Microstructure,hardness and wear resistance of in situ Al18B4O33w/6061 composites

以Al-Al2O3-B2O3为反应体系,采用接触反应法制备了原位自生Al18B4O33w/6061复合材料,利用XRD和SEM对复合材料分别进行物相分析及微观形貌观察,对比6061基体材料,研究了Al18B4O33晶须对复合材料硬度和耐磨性能的影响。结果表明,采用接触反应法,利用Al-Al2O3-B2O3反应体系可直接在6061基体材料中原位自生针状Al18B4O33晶须,Al18B4O33晶须直径为0.1~2μm,晶须伴生于Mg元素。经T6热处理后,Al18B4O33w/6061复合材料的硬度为HB 132.7,较6061基体提高了27.4%,硬度的提高机制为位错强化和细晶强化。Al18B4O33w/6061复合材料的比磨损率和平均摩擦系数分别为1.96×10-8 kg/(N·m)和0.221,较6061基体下降了12.11%和22.46%。采用原位自生工艺制备的Al18B4O33w/6061复合材料,晶须与基体材料之间的润湿性和界面结合强度良好,且晶须本身强度高,在磨损时能够起到支撑作用,减小了基体的应变和磨损,有效地提高了复合材料的耐磨性。

In situ Al18B4O33w/6061 composites were prepared by contact reaction method using Al-Al2O3-B2O3 as reaction system.The phase analysis and micro-morphology observation of the composites were carried out by XRD and SEM respectively.The effect of Al18B4O33 whisker on the hardness and wear resistance of the composites was studied by comparing 6061 matrix.The results show that the needle-like Al18B4O33 whiskers could be directly in situ formed in 6061 matrix by the Al-Al2O3-B2O3 reaction system.The diameter of Al18B4O33 whiskers was 0.1-2μm,and the whiskers formation were associated with Mg element.After T6 heat treatment,the hardness of Al18B4O33w/6061 composite was HB 132.7,which was 27.4%higher than that of 6061 matrix.The mechanism of hardness improvement was dislocation strengthening and fine grain strengthening.The specific wear rate and average friction coefficient of Al18B4O33w/6061 composites were 1.96×10-8 kg/(N·m)and 0.221,respectively,which were 12.11%and 22.46%lower than that of 6061 matrix.Al18B4O33w/6061 composites prepared by in-situ processing had good wettability and interfacial bonding strength between whiskers and matrix,and the strength of whiskers themselves was enough high,which could play a supporting role during wearing,reducing the strain and wear of the matrix,and effectively improving the wear resistance of composites.