Shape memory property characterizes the behavior of many Ti based and Cu based alloys (SMAs). In Cu-Zn-Al SMAs, the original shape recovering is due to a bcc phase that is stable at high temperature. After an appropriate cooling process, this phase (β-phase or austenitic phase) transforms reversibly into a B2 structure (transition phase) and, after a further cooling process or a plastic deformation, it transforms into a DO3 phase (martensitic phase). In β-Cu-Zn-Al SMAs, the martensitic transformation due to plastic deformation is not stable at room temperature: a high temperature “austenitization” process followed by a high speed cooling process allow to obtain a martensitic phase with a higher stability. In this work, a Cu-Zn-Al SMA in “as cast” conditions has been microstructurally and metallographically characterized by means of X-Ray diffraction and Light Optical Microscope (LOM) observations. Fatigue crack propagation resistance and damaging micromechanisms have been investigated corresponding to three different load ratios (R=0.10, 0.50 and 0.75).
Fatigue crack micromechanisms in a Cu-Zn-Al shape memory alloy with pseudo-elastic behavior / Cocco, Vittorio Di; Iacoviello, Francesco; Natali, Stefano; Brotzu, Andrea. - In: FRATTURA E INTEGRITÀ STRUTTURALE. - ISSN 1971-8993. - ELETTRONICO. - 9:34(2015), pp. 415-421. [10.3221/IGF-ESIS.34.46]
Fatigue crack micromechanisms in a Cu-Zn-Al shape memory alloy with pseudo-elastic behavior
NATALI, Stefano;BROTZU, Andrea
2015
Abstract
Shape memory property characterizes the behavior of many Ti based and Cu based alloys (SMAs). In Cu-Zn-Al SMAs, the original shape recovering is due to a bcc phase that is stable at high temperature. After an appropriate cooling process, this phase (β-phase or austenitic phase) transforms reversibly into a B2 structure (transition phase) and, after a further cooling process or a plastic deformation, it transforms into a DO3 phase (martensitic phase). In β-Cu-Zn-Al SMAs, the martensitic transformation due to plastic deformation is not stable at room temperature: a high temperature “austenitization” process followed by a high speed cooling process allow to obtain a martensitic phase with a higher stability. In this work, a Cu-Zn-Al SMA in “as cast” conditions has been microstructurally and metallographically characterized by means of X-Ray diffraction and Light Optical Microscope (LOM) observations. Fatigue crack propagation resistance and damaging micromechanisms have been investigated corresponding to three different load ratios (R=0.10, 0.50 and 0.75).File | Dimensione | Formato | |
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