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对3种含氢量的Ti-2Al-2.5Zr钛合金的室温疲劳裂纹扩展速率进行了实验测定,并对断裂以后的试样进行了断口观察。实验结果表明:含氢Ti-2Al-2.5Zr的稳态裂纹扩展符合Paris幂律关系;氢对裂纹稳态扩展阶段的疲劳裂纹扩展速率(da/dN)基本没有影响, 但对失稳快速扩展行为影响较大;氢含量越高,开始发生疲劳裂纹失稳快速扩展的应力强度因子范围越低;高含氢量的试样在应力强度因子范围(ΔK)高时发生氢化物的择向开裂,降低了材料的断裂韧性,导致裂纹失稳快速扩展所需的ΔK比低氢含量所需的ΔK小。
The room temperature fatigue crack growth rate of three Ti-2Al-2.5Zr titanium alloys with hydrogen content was measured experimentally, and the fracture specimens were observed after fracture. The experimental results show that the steady-state crack growth of hydrogen-containing Ti-2Al-2.5Zr conforms to the law of Paris’s power law. Hydrogen has almost no effect on the fatigue crack growth rate (da / dN) during the steady-state crack propagation. The higher the hydrogen content is, the lower the range of stress intensity factor that begins the rapid expansion of the fatigue crack instability; the high hydrogen content sample occurs the selective cracking of the hydride when the stress intensity factor (ΔK) is high , The fracture toughness of the material is reduced, the ΔK required for rapid expansion of the crack instability is smaller than the ΔK required for the low hydrogen content.