초록 ▼

A method is provided for eliminating internal voids in superplastically forming parts. A blank of material which is capable of being formed superplastically is held opposite a forming surface of a die. The blank is heated to the superplastic forming temperature and pressure is applied to both sides

A method is provided for eliminating internal voids in superplastically forming parts. A blank of material which is capable of being formed superplastically is held opposite a forming surface of a die. The blank is heated to the superplastic forming temperature and pressure is applied to both sides of the blank. This pressure is sufficient to prevent the formation of voids. The pressure on the side of the blank farthest from the die surface is then increased to superplastically form the material against the die surface. In a second embodiment, the pressure is applied after the blank has been formed either by maintaining the forming pressure to compreses the material between the forming pressure and the reaction of the die, or by applying a fluid pressure to both sides of the part, thereby removing voids by plastic deformation and diffusion.

대표청구항 ▼

A method of reducing cavitation during superplastically forming a blank of material, comprising the steps of: providing a blank of material which exhibits an effective value of strain rate sensitivity at a forming temperature; providing a die having a forming surface; positioning said blank in said

A method of reducing cavitation during superplastically forming a blank of material, comprising the steps of: providing a blank of material which exhibits an effective value of strain rate sensitivity at a forming temperature; providing a die having a forming surface; positioning said blank in said die opposite said forming surface; holding said blank at said forming temperature so that said material exhibits said effective value of strain rate sensitivity; applying positive pressure concurrently to both sides of said blank sufficient to prevent the formation of voids in said material; and increasing said positive pressure on the side of said blank farthest from said forming surface to develop tensile strain in said material at a rate which provides said effective value of strain rate sensitivity, whereby said blank stretches by said tensile strain toward said forming surface and forms against said forming surface without cavitation.