โ Scribed by Dian-Fu Wang; Shan-Yi Du; Tuo Wang
No coin nor oath required. For personal study only.
An investigation of the fatigue retardation phenomenon by interference microscope of two different magnifications (64x and 168~) has been made with SEN soecimens of Ti-SAI-2.5 Sn and 30CrMnSiNisteel. The findings are listed as follows:
(I) The basic behaviour: It has been observed that the consecutive fatigue plastic zones which are associated with each other in series do not show any overlapping in the interference patterns. Furthermore, it has been found that the size of fatigue plastic zone shrinks during retardation period after overloading.
(2) The void plastic zone: It has been revealed that a void plastic zone will be formed in both overload (P,,) and the constant amplitude load (P<) just before overloading are high enough to cause blunting of the crack tip.
(3) The blunting mechanism: The blunting mechanism of crack tip during retardation haa been studied and discussed in this work.
๐ SIMILAR VOLUMES
Analysis of the information obtained from instrumented impact test and of its correlations with static and dynamic J integral values and with various tensile properties is made in this study.