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内燃机气缸采用铝硅类的铝合金已经不是新鲜事物,但是,到目前为止,气缸和活塞两个铝制摩擦件之间的表面适应性却从未达到令人满意的程度。一般来说,通常所使用的铝硅合金的含硅量为12%(亚共晶合金)到20%(过共晶合金)。在这些合金中,存在着许多铝和硅的原晶。在和没有镀层的铝合金活塞表面接触时,树枝状的铝原晶便会使活塞造成卡住现象,而大角度的硅原晶能划伤活塞。所以,采用各种方案来解决这些问题:例如,将活塞工作面镀铁或镀铬,缸壁镀铬,或加铸铁缸套等方法,使两者表面相适应。总之,无论是活塞或是气缸,从毛坯制造到加工过程中,都需要采取一些特殊的、复杂的表面准备过程。如果能研究出一些较为简单的方法,使活塞能和缸壁表面相适应,则就会使内燃机使用铝的技术获得重大的进展。
It is not new to use an aluminum-silicon based aluminum cylinder for the cylinder of an internal combustion engine, but so far the surface adaptability between the two aluminum friction pieces of the cylinder and piston has never been satisfactory. In general, the aluminum-silicon alloys commonly used have a silicon content of 12% (hypoeutectic) to 20% (hypereutectic). Among these alloys, many are present as primary crystals of aluminum and silicon. Dendritic aluminum crystals cause the piston to become stuck during contact with the uncoated aluminum piston surface, while high angle silicon crystals can scratch the piston. Therefore, a variety of solutions are used to solve these problems. For example, the surface of the piston can be iron plated or chrome plated, chrome plated on the cylinder wall, or cast iron cylinder liner to match the surfaces of both. In short, both the piston or the cylinder, from the blank manufacturing to processing, need to take some special and complex surface preparation process. If we can develop some simpler methods to adapt the piston to the cylinder wall surface, significant advances will be made in the technology of using aluminum for internal combustion engines.