High-quality silumin on pistons of combustion engines

In the paper the test results are presented for the AlSH2Cu5Ni5MgO.5CrO.05MoO.05WO.05VO.05 newly worked out silumin close to eutectic piston-silumin with the elevated content ofcopper and nickel to approx. 5% with relation to generally applied the AISH2 piston silumin. The novel silumin contains also Cr, Mo, In and V micro alloy additions in quantity approx. 0.05 percent for every element. Research of microstructure, HB hardness and coefficient of lineal thermal expansion a for the AlSil2Cu5Ni5MgO.5CrO.05MoO.05WO.05VO.05 silumin in the cast state, after the separation strengthening and additional short duration high-temperature heat-treatment were performed. Research of the microstructure of the AlSH2Cu5Ni5MgO.5CrO.05MoO.05WO.05VO.05 silumin showed the occurrence in it following constituent phases: alfa(Al), beta(Si), Al2Cu and AlMoCrWVMgNiSiCuFe. The separation strengthening brought about the coagulation of silicon emissions. The short duration high-temperature heat-treatment caused additional coagulation of silicon emissions and also its coalescence. Measurement of the HB hardness showed high hardness investigated alloy in the rough state, approx. 30% higher from the AlSi2 piston silumin. Measurement of the a coefficient of thermal expansion showed beneficial effects of novel alloy connected with the value decreasing of this coefficient as well so called hysteresis. Further studies on novel alloy will concentrate on alloy-additional and processes of the heat treatment.