2706 AZ31マグネシウム合金の鍛造加工における変形抵抗と破壊機構(S19-2 アルミニウム合金,マグネシウム合金(2),S19 アルミニウム合金およびマグネシウム合金の創製と加工技術)

抄録

To clarify the forming limit of magnesium alloy in cold forging, workability of magnesium alloy is examined for upsetting and backward extrusion. In the upsettability test, sudden fracture by crack propagation occurs at a small equivalent strain of about 0.15. On the other hand, in cold backward extrusion with a conical punch, the local strain can reach a very large value, 3.0 or greater, without fracture. To explain the experimental results, the mechanism of fracturing is discussed on the basis of strain localization, and a fracture criterion of magnesium alloy in cold forging is put forward.