| abstract |
A cylinder liner, for casting into a reciprocating piston engine, is formed of a highly hypereutectic aluminium/silicon alloy which is free of hard material particles independent of the melt and has such a composition that fine primary silicon crystals and intermetallic phases automatically form from the melt as hard particles. By spray-compacting, a blank of finely-sprayed melt droplets is caused to grow, a fine distribution of the hard particles being produced by controlled introduction of small melt droplets. The blank can be transformed by an extrusion step into a form approximating the cylinder liner. After subsequent premachining with chip removal, the running surface is precision machined and subsequently honed in at least one stage, after which the hard particles located in the running surface are laid bare, plateau faces of the particles being formed, which faces protrude from the remaining surface of the matrix structure of the alloy. The laying-bare of the primary crystals and/or particles is effected chemically, using aqueous alkali. The alloy composition is Si 23-28% Mg 0.8-2% Cu 3-4.5% Mn 0-0.01% Zn 0-0.01% AND either Fe 0-0.25% and Ni 0-0.01% or Fe 1-1.4% and Ni 1-5%, the balance in either case being Al. |