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室温下,超细晶工业纯钛(UFG CP Ti)光滑试样在加载频率f=25 Hz、应力比R=–1的条件下进行高周应力疲劳测试,拟合超细晶工业纯钛应力幅σ_a与疲劳断裂循环周次Nf之间的关系曲线,并对疲劳断口形貌进行观察分析。结果表明:200℃退火60 min超细晶工业纯钛的疲劳极限值σ-1为376.5 MPa,比未退火超细晶工业纯钛的疲劳极限值提高56.5 MPa。疲劳裂纹源萌生于超细晶工业纯钛的表面,200℃退火60 min超细晶工业纯钛的疲劳辉纹间距较小,疲劳裂纹不易扩展,室温疲劳性能优良。
At room temperature, UFG CP Ti smooth specimens were subjected to high-cycle stress fatigue test under the conditions of loading frequency f = 25 Hz and stress ratio R = -1 to fit the ultrafine-grained industrial pure titanium stress Amplitude σ_a and fatigue fracture cycle Nf relationship between the curve, and fatigue fracture morphology were observed and analyzed. The results show that the fatigue limit σ-1 of ultrafine-grained commercial pure titanium annealed at 200 ℃ for 60 min is 376.5 MPa, which is 56.5 MPa higher than the fatigue limit of unannealed ultrafine-grained commercial pure titanium. Fatigue cracks originated on the surface of ultrafine-grained industrial pure titanium. The annealed pure titanium at 200 ℃ annealed for 60 min showed less fatigue fray spacing, less fatigue crack growth and excellent fatigue properties at room temperature.