原位生成TiB 2颗粒对活塞用铝合金微观结构和性能的影响

Influence of in-situ TiB 2 particles on microstructure and properties of aluminium alloy for piston

在活塞用铝合金中,通过熔盐反应法原位生成TiB 2颗粒制备成铝基复合材料,重点研究了原位生成TiB 2颗粒质量分数对活塞用铝合金微观结构、力学性能和耐磨性能的影响.实验结果表明,采用熔盐反应法结合高强电磁搅拌技术可在铝合金内原位生成亚微米级TiB 2颗粒.当TiB 2颗粒质量分数由1.0%增加至7.0%时,铝基体晶粒显著细化,富铁相由针状转化为块状,铝基复合材料的常温力学性能显著提升.高温拉伸实验结果表明,原位生成TiB 2颗粒可显著提升铝合金的高温强度保持率,350℃时保温100 h后,铝基复合材料的屈服强度较活塞用铝合金高30%.摩擦实验结果表明,TiB 2颗粒的加入可使活塞用铝合金的磨损量降低70%.

Aluminum matrix composites were fabricated on the basis of in-situ generation of TiB 2 particles inside aluminium alloy for piston by molten salt reaction,and the influence of TiB 2 particles mass fraction on microstructure,mechanical properties and wear resistance of aluminium alloy for piston was studied emphatically.The experimental results showed that submicron TiB 2 particles can be generated in situ in aluminum alloy by molten salt reaction combined with high strength electromagnetic stirring.When the TiB 2 particle mass fraction increased from 1.0%to 7.0%,the aluminum matrix grains were significantly refined and the Fe-rich phases were transformed from needle to block.The mechanical properties of aluminum matrix composites at room temperature were significantly improved.The results of high temperature tensile test showed that the in-situ generated TiB 2 particles can significantly improve the retention rate of strength of aluminum alloy at high temperature.The yield strength of aluminum matrix composite was 30%higher than that of aluminum alloy for piston after heating preservation at 350℃for 100 h.The friction test showed that the introduction of TiB 2 particles can reduce the wear amount of aluminum alloy for piston by 70%.