A turbine blade rotor assembly is disclosed for a gas turbine engine. The assembly includes a rotor having nickel alloy turbine blades secured thereto. Each of the blades includes a root and an airfoil. The roots are supported by the rotor. A ceramic matrix composite platform separate from the turbine blades is supported between each pair of the turbine blades adjacent to the airfoils. In another example, the airfoil includes a perimeter. A shroud having an aperture receives the airfoil with a single shroud substantially surrounding the airfoil at the perimeter. In one example, the turbine blade includes high and low pressure sides opposite one another that extend from a tip to a root. The airfoil is free from any protrusions extending from the high and low pressure sides on a portion of the blade axially outward from the root.