A gas turbine that includes a rotor blade that includes an airfoil. The airfoil may include non-integral portions in which: a base portion is made from a first material; and a top portion is made from a second material. The airfoil may include a connector securing the base portion to the top portion of the airfoil, wherein the connector comprises a wire-lock connector that includes: a tab extending from one of the base portion and the top portion; a complimentary slot for receiving the tab formed in the other one of the base portion and the top portion; a first groove formed in a side of the tab; a second groove formed in a side of the slot; a retaining aperture formed cooperatively via an alignment of the first and second grooves upon the tab being received into the slot; and a retaining wire housed within the retaining aperture.