Lower cost aluminum silicon carbide (Al-SiC) metal matrix composite (MMC) produced by stir-casting is emerging as an important material in cost effectively improving the reliability of high power electronic devices; e.g. electronic (IGBT) baseplates, thermal spreaders & stiffeners for flip-chip microelectronics, and heat slugs or MCPCB base layers for high brightness LEDs. This paper will review the properties and competitive cost of these new Al-SiC materials as well as the ability to tailor the coefficient of thermal expansion (CTE) of the Al-SiC to minimize thermal fatigue on solder joints and reduce component distortion. The impact on the final component cost through the use of conventional forming techniques such as (a) rolling sheet followed by stamping, and, (b) die casting, will be described, as will be the opportunity of eliminating a thermal interface material (TIM) layer by integrating the thermal spreader with the heat sink for high power microelectronic packages.