Wear behaviour of some piston alloys in different environments

Aluminum and its alloys are one of the most important alloys because oftheir unique properties such as weight lightness, corrosion resistance, highstrength to density ratio, good wear resistance, ... etc. Aluminum-silicon alloyshave a wide range of practical applications, specially in piston assembly ofinternal combustion engines.Therefore, in the present investigation, the wear behavior of somepiston alloys produced in Egypt (AISi12CuNi and AISi12CuNi alloys) indifferent environments were studied. This study focused mainly on illustratingthe effect of oxygen partial pressure on the mechanical wear behavior of thesealloys, since changing the oxygen partial pressure may lead to changing theoperating wear mechanism and/or even the wear type that may be existed. Inany mechanical system subjected to friction, the allowable wear should bewithin mild wear not severe wear, if existed. However, if the oxygen partialpressure changes in the surrounding environment, the mild wear condition maynot occur.All wear tests have conducted on pin-on-ring test rig supplied with anenvironmental chamber. This chamber enables us to control the oxygen partialpressure by changing the surrounding atmosphere. Four different atmosphereshave been used, namely, argon, nitrogen, air and oxygen. An SEMexamination has been introduced on the worn pin surfaces to depict thedifferent wear mechanisms existed. XRD analysis of some samples has beenalso examined.