Biaxial low cycle fatigue properties and dislocation substructures of zircaloy-4 under in-phase and out-of-phase loading
Biaxial low cycle fatigue properties and dislocation substructures of zircaloy-4 under in-phase and out-of-phase loading
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DOI：
10.1016/s0921-5093(00)01005-4
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发表时间：
2000-11-15
期刊：
影响因子：
6.4
通讯作者：
Sun, J
中科院分区：
文献类型：
--
作者：
Xiao, L;Umakoshi, Y;Sun, J
在同相（IP）和异相（OP）载荷下对锆合金-4（Zr-4）进行了双轴疲劳试验。研究了主应变比（φ（3）/φ（1））、相位角（φ）和等效应变范围（Δ φ（eq））对双轴循环硬化、疲劳寿命和变形亚结构的影响。在IP和OP循环载荷下，Zr-4合金的循环应力-应变曲线比单调变形下的应力-应变曲线向更高的应力水平移动。OP载荷下的循环硬化速度比IP载荷下快，疲劳寿命比IP载荷下短。随着φ和Δ ε（eq）的增加，疲劳寿命降低。在IP加载条件下，常观察到平行位错带，但随着Δ ε（eq）的增加，形成位错缠结和胚胎位错胞。在OP加载下，随着Φ和Δ ε（eq）的增加，位错构型从平行位错壁变为发达的位错缠结。讨论了OP加载下的附加循环硬化和疲劳寿命下降的机理。(C)2000 Elsevier Science S.A. All rights reserved.
Biaxial fatigue tests were performed for Zircaloy-4 (Zr-4) under in-phase (IP) and out-of-phase (OP) loading. Effects of the principal strain ratio (epsilon (3)/epsilon (1)), phase angle (Phi) and the equivalent strain range (Delta epsilon (eq)) on the biaxial cyclic hardening, fatigue life and deformation substructure were examined. The cyclic stress-strain curves of Zr-4 fatigued under IP and OP cyclic loading were shifted to a higher stress level than those in monotonic deformation. Cyclic hardening was more accelerated and fatigue life was shorter under OP loading than under IP loading. As the Phi and Delta epsilon (eq) increased, the fatigue life decreased. Parallel dislocation bands were frequently observed under IP loading but dislocation tangles and embryonic dislocation cells were formed with increasing Delta epsilon (eq). Under OP loading the dislocation configuration changed from parallel dislocation walls to well-developed dislocation tangles as the Phi and Delta epsilon (eq) increased. The mechanisms of additional cyclic hardening and fatigue life drop under OP loading are discussed. (C) 2000 Elsevier Science S.A. All rights reserved.