High-strength, lightweight alloy components, such as automotive components, capable of high temperature performance comprising aluminum, silicon, and iron and/or nickel are provided, along with methods of making such high-strength, lightweight alloy components. A high-energy stream, such as a laser or electron beam, may be selectively directed towards a precursor material to melt a portion of the precursor material in a localized region. The molten precursor material is cooled at a rate of greater than or equal to about 1.0×105 K/second to form a solid high-strength, lightweight alloy component comprising a stable ternary cubic phase having high heat resistance and high strength. The stable ternary phase may be AlxFeySiz, where x ranges from about 4 to about 5 or about 7.2 to about 7.6, y is about 1.5 to about 2.2, and z is about 1. The stable ternary phase may also be Al6Ni3Si.