Hollow Structural Members of Superplastic Aluminium Alloy by RB/SPF

摘要

Hollow structural members such as truss and honeycomb, all made from aluminium alloy sheets, was formed tentatively by RB/SPF newly developed here, which indicates Roll Bonding/ /SuperPlastic Forming. RB/SPF with using Gas Generant originally developed for automobiles airbag involves the following steps: 1. cladding of 3-layer metal sheet by hot roll bonding after adequate surface treatment, whose interfaces would firmly be bonded in part and selectively unbonded area left at the unbonded interface there left thin layer of Gas Generant that on heating at specific temperature decomposes itself and yields some inert gas components. Then 2. heating the clad metal to specific temperature with using proper die assembly, it can be bulge-formed spontaneously into hollow plate whose geometrical shape of cross sectional area was devised in advance so as to increase the total stiffness and rigidity. The objective is to optimize many processing variables such as surface treatment at the beginning, selection on skin and core materials, Gas Generant and STOP OFF for avoiding bond, forming temperature and maximum geometrical size of the product. The several trials show this way of method can be compared favorably with conventional extrusion in manufacturing similar kinds of members as these.