Variation of fracture toughness of a 7075 aluminium alloy with hydrostatic pressure and relationship with tensile ductility
✍ Scribed by J. P. Auger; D. François
- Publisher
- Springer Netherlands
- Year
- 1977
- Tongue
- English
- Weight
- 622 KB
- Volume
- 13
- Category
- Article
- ISSN
- 1573-2673
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✦ Synopsis
The mechanical properties of a 7075 aluminium alloy were tested under hydrostatic pressure from atmospheric pressure to 600 MPa. Cylindrical t0nsion specimens, plane strain tension specimens, precracked bend and compact tension specimens were used. The elastic modulus was measured with ultrasonic waves. Several orientations with respect to the rolling direction were investigated. Young's modulus, the elastic limit, and the strain hardening coefficient increased only slightly with pressure. Both tensile and plane strain ductility were greatly enhanced under pressure. The fracture toughness increased with pressure. From the variation of the plane strain ductility the fracture stress of the interface between the void nucleating inclusions and the matrix could be evaluated to be about 3000 MNm -2 in the short transverse direction and 9000 MNm -2 in other directions. The variation of the fracture toughness could be related with the plane strain ductility according to either the model of Brock or the model of Hahn and Rosenfield. Rice's hypothesis relating the critical COD to the mean distance between void nucleating particles could also provide a satisfactory explanation for the enhancement of fracture toughness under pressure.