柴油发动机活塞用铝基材料研究进展及失效分析

活塞作为柴油发动机的核心部件之一,恶劣的服役工况对其材料有特殊的要求。概述了活塞用铝基材料的发展状况,包括合金系(Al-Cu-Si系、Al-Cu-Ni-Mg系、共晶型Al-Si-Cu-Mg系和过共晶型A1-Si-Cu-Mg系)与复合材料系(SiC/Al基复合材料、Al_2O_3/Al基复合材料和TiC、TiB_2/Al基复合材料等),并介绍了不同材料的适用范围。同时,归纳了常见活塞铝基材料的失效机制,包括磨损、机械损伤以及顶部开裂等。其中,活塞因磨损造成的失效在统计活塞失效机制中所占比例较大,具体可分为粘着磨损失效和磨粒磨损失效。针对活塞磨损失效提出了相关改善措施,如材料成分选取和制备方法选取等。此外,针对柴油发动机在实际运行工况中,因活塞所处部位存在润滑油不完全燃烧造成的含硫、氮等腐蚀性气氛而加速磨损的问题,可依托该气氛与相应增强相的反应,使其接触表面生成自润滑膜而减少甚至抑制磨损,进而延长柴油发动机活塞的使用寿命。

Research Progress and Failure Analysis of Aluminum Matrix Materials for Diesel Engine Piston

As one of important components of diesel engines, the service conditions of piston is very severe and such atmosphere requires the pistons have special requirements for its materials. The development of aluminum alloys for pistons are summarized, including alloys (Al-Cu-Si, Al-Cu-Ni-Mg, eutectic Al-Si-Cu-Mg and hypereutectic Al-Si-Cu-Mg) and composite materials (SiC/Al composites, Al2O3/Al composites and TiC, TiB2/Al composites), the application of these materials are described. At the same time, failure mechanism of piston aluminum matrix composites are listed, including wear failure, mechanical damage and cracking at the top. According to the statistics of piston failure mechanism, the wear failure occupies a major position, which can be divided into adhesive wear and abrasive wear failure. This paper proposes improvement measures for the piston wear failure, such as material composition selection and preparation methods. In addition, when the diesel engine material works under its actual operating conditions containing sulfur and nitrogen and other corrosive atmosphere by the lubricating oil incomplete combustion, it will deteriorate the abrasion problems. But the reaction of enhanced phase and this complex corrosive atmosphere in the piston will generate self-lubrication film, which can reduce or even inhibit wear failure, thereby extending the life of diesel engine pistons.