THE EFFECT OF GRAIN-BOUNDARY STRUCTURE ON THE TENSILE FRACTURE BEHAVIOUR OF HOT-ISOSTATICALLY PRESSED 713LC ALLOY COMPACTS

Examination of the ambient-temperature tensile fracture behaviour of hot-isostatically pressed 713LC alloy compacts indicates that the nature of the fracture paths varies with the thermal history of the material. The fracture mode may be transgranular, interparticle, or intergranular and is apparently controlled by the structures of the grain boundaries and powder-particle boundaries. Interparticle fracture, observed after certain pressing and heat-treatment operations, can be regarded as a variant of conventional intergranular fracture. This type of fracture mode results from the formation of heavy growths of mixed MC + M 23 C 6 carbide on powder-particle boundaries during processing.