摘要
测定了纯Zr及Zr—4合金在室温和400℃下低周疲劳寿命曲线分别选用循环塑性耗散应变能和疲劳断回表面分形维数作为疲劳损伤参量，根据Zr及Zr-4合金表现为循环硬化、饱和、再软化三阶段的特征，建立了不同变形阶段的累积塑性耗散应变能表达式结果表明，不同塑性应变幅下循环塑性耗散应变能与疲劳寿命之间满足指数关系疲劳断口表面分形分析表明：分形维数与疲劳寿命之间也满足指数关系循环塑性耗散能、分形维数与疲劳寿命三者之间的定量关系为：D≈0．027lnNf＋1．099≈0．120lnWpt-0．025。
Low cycle fatigue lifetime curves of zirconium and zircaloy-4 at room temperature and 400 ℃ were measured, respectively. Cyclic plastic dissipated energy and fractal dimension of fracture surfaces are selected as damage variable to evaluate the fatigue lifetime. The accumulated formula of plastic dissipated energy is established on the basis of considering cyclic deformation character of zirconium and zircaloy-4. The test results indicate that the relationship between cyclic plastic dissipated energy and fatigue lifetime fits power law. Fractal analysis of fracture surface shows that the relationship between fractal dimension and fatigue lifetime can be also expressed as power law. An empirical formula describing the relationship between dissipated energy, fractal dimension and fatigue lifetime, D ≈ 0.027 lnN f + 1.099 ≈0.120 lnWpf- 0.025, is obtained, and their physical mechanism is discussed thermodynamically.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1998年第7期705-712,共8页
Acta Metallurgica Sinica
基金
国家自然科学(青年)基金!59601009
核工业科学基金!H7196EY702
关键词
分形维数
疲劳寿命
锆合金
循环耗散能
zirconium, zircaloy-4, cyclic plastic dissipated energy, fatigue lifetime
