Effect of grain size on slow fatigue crack propagation and plastic deformation near crack tip |
| |
| Authors: | R Deng G Yu H Li |
| |
| Affiliation: | 1. ISAE-ENSMA – UPR CNRS 3346, Institut Pprime, Département Physique et Mécanique des Matériaux, Téléport 2, Avenue Clément Ader, BP 40 109, 86961 Futuroscope, France;2. MATEIS, INSA Lyon/Université de Lyon/CNRS, F-69621 Villeurbanne Cedex, France;3. CTIF, 44 avenue de la Division Leclerc, F-92318 Sevres Cedex, France;1. Unité de Génie de Production Mécanique et Matériaux (UGPM2-UR17ES43), Ecole Nationale d''Ingénieurs de Souss, Université de Sousse, Tunisia;2. Laboratoire de Mécanique, Matériaux et Procédés, Ecole Supérieure des Sciences et Techniques de Tunis, Université de Tunis, Tunisia;1. School of Engineering, Deakin University, Pigdons Rd., Waurn Ponds, VIC 3217, Australia;2. Institute of Frontier Materials, Deakin University, Pigdons Rd., Waurn Ponds, VIC 3217, Australia;1. Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany;2. Department of Neurosurgery, University of Freiburg, Germany |
| |
| Abstract: | Fatigue crack growth and its threshold are investigated at a stress ratio of 0.5 for the three-point bend specimen made of Austenitic stainless steel. The effect of grain size on the crack tip plastic deformation is investigated. The results show that the threshold value Δkth increases linearly with the square root of grain size d and the growth rate is slower for materials with larger grain size. The plastic zone size and ratio for different grain sizes are different at the threshold. The maximum stress intensity factor is kmax and σys is the yield strength. At the same time, the characteristics of the plastic deformation development is discontinuous and anti-symmetric as the growth rate is increased from 2·10—8 to 10−7 mm/cycle.A dimensionless relation of the form for collating fatigue crack starting growth data is proposed in which Δkth represents the stress intensity factor range at the threshold. Based on experimental results, this relation attains the value of 0.6 for a fatigue crack to start growth in the Austenitic stainless steel investigated in this work. Metallurgical examinations were also carried out to show a transgranular shear mode of cyclic cleavage and plastic shear. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
