ＷＣ‐１ｍａｓｓ％Ｃｒ３Ｃ２‐１２ｍａｓｓ％Ｎｉ超硬合金の疲労特性

Abstract

The bending and compressive fatigue characteristics of the normal sintered and HIP-treated WC-1 mass%Cr3C2-12mass%Ni alloy (Ni alloy) applied for non-magnetic or corrosion-resistant tools were mainly investigated and compared with those of WC-1 mass%Cr3C2-12mass%Co alloy (Co alloy) which was previously reported by us.The results obtained were as follows. :1) The bending fatigue life was more superior in the HIP-treated Ni alloy than the normal sintered Ni alloy especially in the range of high applied stress. But the difference between them became smaller with decreasing the applied stress, and it was inclined to reverse around fatigue limit. 2) The bending fatigue life of HIP-treated Ni alloy lowered as compared with that of the HIP-treated Co alloy. 3) All the fracture origins of HIP-treated Ni alloy in the bending fatigue were Ni pools and the fracture form of the origin under the high applied stress showed a dimple pattern. The area of the dimple pattern decreased with decreasing the applied stress and conversely that of the brittleness fracture form increased, but it did not show a step-shaped form which was clearly observed in Co alloy. 4) The compressive fatigue life of the Ni alloy lowered remarkably as compared with that of the Co alloy. This result was considered to correspond to the fact that the plastic deformation was larger in Ni alloy than Co alloy.