Superplastic forming (SPF) is an advanced sheet manufacturing process typically used for low- volume, high-value products. SPF dies made from refractory castables have a lower production cost than metal dies, but their brittle nature is a limiting factor. This work investigates surface degradation mechanisms in ceramic dies and how they are affected by the application of thermal spray coatings. Among the more notable accomplishments of the study is the development of a test rig that simulates die-part interface conditions during superplastic forming and monitors die wear, making it possible to predict ceramic die lifetime for different coatings.

Arc spraying metal onto a master pattern is an emerging method for making molds and dies. The process, called arc spray metal tooling, involves several steps, which are shown in this paper. Three sheet metal forming dies of varying complexity were made to demonstrate and assess the process. Press tests were performed at a mold and die making facility. Arc-sprayed metal shells produced from carbon steel wire were found to have a tensile strength of approximately 23 kg/mm 2 , a Vickers hardness of 330 HV, and a dimensional accuracy of about ± 0.1 mm.