High density intermetallic phase component production - by expansion-free pressureless sintering of coated base component powder.

: Boehm, A.; Kieback, B.; Scholl, R.; Juengling, T.

Abstract
Production of high density intermetallic phase-based materials and components is carried out using a composite powder of the base component in elemental or pre-alloyed form and a second component (preferably aluminium) in elemental or pre-alloyed form, in which one component completely and uniformly encloses the other component and in which each powder particle has a component ratio corresponding to the desired final composition (intermetallic phase), so that no expansion of the consolidated material occurs during sintering. Also claimed is a second similar process in which the second component is a soft metallic/elemental powder, the process comprising (a) mixing the individual powders in a stoichiometric ratio such that the base component powder particles are enclosed by the soft powder particles; and (b) compacting the powder mixture to a component or body, shaping with a deformation ratio of about 20 and machining the body transverse to the shaping direction to produce material or powder which is subjected to uniaxial pressing and pressure-less sintering. ADVANTAGE - The processes permit production of high density, non-porous intermetallic phase components from inexpensive starting materials by pressure-less sintering, without expansion during intermetallic phase formation and with isotropic shrinkage characteristics during heat treatment. Thus near-net shape complicated components can be produced by direct pressing and sintering.