Al-Si alloys find wide application in many parts of internal combustion engines such as cylinder blocks, pistons, liners, clutches, rocket arms, pivots etc. Any reduction in friction and wear of these alloys not only increase the life of the bearings, but also reduces the emission and decreases the fuel consumption. Investigations on the variation of the counter-face mating material on friction and wear explored. The details of experimental methods, materials and testing procedures elucidated. This book reports the dry sliding behavior of Al sliding against itself, Al-5 Si and on steel. The wear behavior of hypo-eutectic, eutectic and hyper-eutectic Al-Si alloys (Al-5 Si, Al-12 Si and Al-20 Si) with and without CO2 laser and Nd:YAG laser treatment was illustrated. Unidirectional dry sliding wear behavior of as cast and laser processed with CO2 laser on Al-Si alloys sliding with steel disc had been presented. Solid particle erosion behavior of Al-Si alloys with as cast, laser re-melted and alloyed with SiC precursor using CO2 laser was discussed.