STRAIN AND FRACTURE OF LIQUID PHASE SINTERED ALLOY 90W-TNi-3Fe

The feature of deformation and fracture of a liquid phase sintered alloy 90W-7Ni-3Fe has been studied. It was found that the matrix of the alloy is the first to yield and to undergo plastic deformation. The cracks may be initiated along the W grain/matrix interfaces as the bonding force here is weak. While the bonding force is strengthened to a greater extent than the cleavage failure stress of W, the transgranular cleavage cracking of W grains and the plastic teaing of the matrix may happen simultaneously. Hydrogen is shown as one of the main sources of the inteffacial embrittlement of as-sintered specimen. The removal of the hydrogen both stored in the voids and dissolved in metals of the W grain/matrix interfaces is easily done by heat treatment under vacuum. Thereafter, the bonding force at interface as well as the tensile strength and plasticity of specimen can be modified.