Sheet metal forming of superplastic alloys by gas generants

SPF(SuperPlastic Forming) by gas generants has been applied to superplastic Al alloy sheets. The gas generant is any chemical substance, which on heating decomposes and generates some inert gas components. This inert gases serve as the internal forming agent. Simple free bulging and practical forming tests by these gas generants reveal that this refined processing can be available in the industrial forming operations. RB/SPF (Roll Bonding/SuperPlastic Forming) by gas generants was also tried. This is done by manufacturing clad metal sheet by initial roll bonding. Any geometrically designed in-plane area of the rolled sheet is left unbonded. Also within this thin interface clearance gas generant is left unchanged which would act as a source of gas pressure at elevated temperature Selection of appropriate sources which acts as STOP OFF in roll bonding and the gas pressure agent in forming and how to enclose the pressure source in the thin clearance are the key factors to be addressed in this new processing.