PARTICLE BOUNDARIES AND FRACTURE OF A POWDER METALLURGY SUPERALLOY

Nature of PPB precipitation of P/M Rene'95 and its effects on mechanical properties,frac- ture morphology and microfracture characteristics are discussed.Dense PPB precipitates make the boundaries brittle and lower the plasticity of the alloy.Fracture path is along the boundaries of particles.As PPB parameter increases,the interfaces between particles are strengthened.The fracture mode is changed from interparticle to transparticle.As a result,the plasticity at high temperatures and stress rupture life of the alloy are improved.