| Title |
The Fracture Behaviors of the Heat - Treated NiAl Alloys From Ring - on - Ring Disk Bend Test ( Ⅱ ) |
| Authors |
박희섭(Hee Sub Park) ; 고홍석(Hong Seok Ko) ; 홍경태(Kyung Tae Hong) ; 이경섭(Kyung Sub Lee) |
| Abstract |
A study has been made to investigate the fracture behaviors of heat-treated polycrystalline NiAl from the controlled indentation flaw method in conjunction with the ring-on-ring disk bend test. Fracture initiated at the indentation load exceeding 196.14N. The fracture toughness was determined from an analysis of the dependence of fracture stress on the indentation load. The true fracture stress was determined by measuring acoustic emission during indentation and bending test. The fracture toughness was measured as 4.61±1.78 (MPam^(1/2)) for unheat-treated NiAl and 6.73±1.34 (MPam^(-1/2)) for 5 times cyclic heat-treated NiAl. The fracture mode of polycrystalline NiAl was primarily intergranular at room temperature, but the portion of intergranular fracture to transgranular fracture decreased in the heat-treated NiAl. |