挤压铸造TiB_(2P)/Al复合材料的组织与性能

Microstructure and Properties of TiB_(2P)/Al Composites Fabricated by Squeeze Casting Technology

采用挤压铸造法制备TiB2P/Al复合材料,并借助XRD,SEM,TEM和三点弯曲、摩擦磨损等分析测试手段研究了该材料的组织和性能。结果表明,复合材料组织致密,颗粒分布均匀,相组成主要为Al和TiB2。TEM观察表明,T6态复合材料基体中发现大量细小的β′析出相和位错。部分界面上存在不连续的块状反应物MgAl2O4。45%TiB2P/Al(体积分数,下同)复合材料的抗弯强度为934MPa,弹性模量为183GPa,比30%TiB2P/Al复合材料的分别提高了34%和28%。常温干摩擦条件下,TiB2P/Al复合材料摩擦系数变化平缓(在0.2左右波动),明显低于铝合金的摩擦系数;且复合材料的磨损表面较为平整、光滑,未观察到大塑性变形,呈现出良好的自润滑性能。

TiB2p/Al composites were fabricated by squeeze casting technology, and their microstructures and properties were investigated by XRD, SEM, TEM, three-point bending tests, friction and wear tester. The results showed that TiB2 reinforcements distributed homogeneously in the dense TiB2p/Al composites, and the main phases in composites were composed of Al and TiB2 phase. TEM observation reveals that after peak aging （T6） treatment, many β precipitates and dislocations were found in the matrix alloy. Some massive and discontinuous reactants, MgAl2O4, were observed on some interfaces of TiB2p/Al composites. For 45% TiB2p/Al composite, its bending strength was 934 MPa and the elastic modulus was 1823 GPa, which increased by 34% and 27% respectively, compared with those of the composite with 30% TiB2. In dry sliding mode, sliding with GCrl 5 bearing steel, friction coefficient of TiB2p/Al composites had no obviously change （fluctuated about 0.2）, which is obviously lower than that of the Al alloy under the same friction condition. No clear plastic deformation and adhesive wear were observed at the worn surfaces of TiB2p/Al composites. TiB2p/Al composites show the self-lubricating properties.