My buddy pointed me in this direction which talks about Hypereutectic pistons in full size engines, is this what Microcasting is all about?

Contains 12.5 percent_or more silicon content. Special melting processes are necessary to ‘super-saturate’ the aluminum with additional silicon content. Special molds, casting and cooling techniques are required to obtain finely and uniformly dispersed silicon particles throughout the material. Our hyper-eutectic material is also being used in light and medium diesel engines to replace some of the eutectic pistons with iron groove inserts used for additional heat and wear resistance of the ring groove. Heat and wear in the ring groove contribute to groove ‘pound-out. In the Sealed Power hypereutectic pistons, the hard, finely dispersed silicon particles serve as ‘micro-inserts’ at the surfaces of the piston, especially in the surfaces of the precision-machined ring grooves. The increased strength, heat and wear resistance provided by the high-silicon content hypereutectic piston material allows for elimination of the groove inserts in several piston applications.