The piston carries combustion load to the rod; with the rings it seals the bore.
Cylinder pressure runs to tens of bar — the crown sees large force plus heat. That is why crown and skirt geometry is worked for thermal and mechanical distortion, not just a static profile.
Gasoline flame temperatures are far above the melt range of typical aluminium piston alloys, so cooling strategy and clearance in the bore matter as much as alloy grade.
In AVTRAMAT releases we design for stable operation under load and consistent wear behaviour in the piston–liner pair — the details sit in the release documentation for each line.