A hybrid fluid-flow assembly having a base fitting that has been formed by axial load bulge forming from a sheet of metal, and a custom fitting that has been machined from a shaped-memory alloy. At least one connection port of the custom fitting is connected to at least one connection port of the base fitting by an interference fit. The interference fit is formed by cooling the custom fitting to a temperature below its transition temperature, deforming the custom fitting so that the diameter of its connection port is slightly larger than the connection port on the base fitting, installing the connection port of the custom fitting on the connection port of the base fitting, and allowing the custom fitting to warm to room temperature. The shaped-memory alloy swages and coins the outer surface of the base fitting at the interface of the ports, thereby forming a compressive, interference fit.