I read so many research studying the effects of sliding speed on wear using pin on ring testing machine all of papers said: when the sliding speed increase the wear rate will increase because the true area of contact will increase with the sliding speed", but one paper that using pin made from Al-SI alloy said : when the sliding speed increase the wear rate will decrease reached a minimum value and then increase because the strain rate will increase which in turn increases the hardness. I didn't understand; is the wear increase or decrease with the sliding speed? is the using of aluminum silicone alloy in the last paper make the wear decrease? I mean is the decrease of wear rate with sliding speed valid for this case only? Please help me.
Mass removal due to wear relates to sliding distance. This gives to wear rate relates to sliding speed.
However, wear rate is not only only a function of sliding speed. Surface hardness also plays a role. AL-SI, according to this paper, will be hardened in the beginning session. With the surface hardness increased, the wear rate decreases. When it can no long be hardened (you cannot fever increase its hardness), it enters the usual wear phase where the wear rate increases with the sliding speed.