Ti-6Al-4V合金のき裂発生および初期き裂伝ぱ過程に及ぼすβ-STA熱処理の影響
Ti-6Al-4V合金のき裂発生および初期き裂伝ぱ過程に及ぼすβ-STA熱処理の影響
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β-STA热处理对Ti-6Al-4V合金裂纹萌生和初始裂纹扩展过程的影响
DOI：
10.2472/jsms.43.408
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
政彦 本田
中科院分区：
文献类型：
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作者：
哲治 田中;弘信 西谷;渉 藤崎;高広 寺西;政彦 本田
为阐明β-STA工艺对Ti-6Al-4V合金疲劳行为的影响，通过一系列旋转弯曲疲劳试验，对β-STA材料和退火Ti-6Al-4V合金的微裂纹萌生和扩展过程进行了连续观察。结果表明：（1）在高于疲劳极限的应力作用下，退火态材料的微裂纹从α相开始出现，而β-STA材料的微裂纹则沿着细针状组织出现。当对应于疲劳极限的应力反复施加到试样上时，在两种材料中均未出现微裂纹。因此，疲劳极限由微裂纹萌生极限决定。(2)β-STA材料的疲劳极限比退火材料的疲劳极限高约30%。(3)在这两种材料中，方程dl/dN=Cσ6l（C：常数，dl/dN：裂纹扩展速率）成立，并且常数C几乎彼此相等。(4)上述结论（1）、（2）和（3）意味着β-STA处理对抵抗微裂纹扩展的影响很小，但有助于提高微裂纹起始的极限应力。
To clarify the effects of β-STA processing on fatigue behaviors of Ti-6Al-4V alloy, microcrack initiation and propagation processes were successively observed in a series of rotating bending fatigue tests of β-STA material and annealed Ti-6Al-4V alloy. The main results obtained are as follows:(1) When the stress higher than a fatigue limit is repetitively applied to the specimen, microcracks appear from the α phase for the annealed material, while they appear along the fine acicular microstructure for the β-STA material. When the stress corresponding to a fatigue limit is repetitively applied to the specimen, no microcrack appears in either of the materials. Accordingly, the fatigue limit is determined by the microcrack initiation limit.(2) The fatigue limit of the β-STA material becomes about 30% higher than that of the annealed material.(3) In both materials, the equation dl/dN=Cσ6l (C: constant, dl/dN: crack growth rate) holds, and constants C are nearly equal to each other.(4) The above conclusions (1), (2) and (3) mean that β-STA processing has little influence on resistance against the microcrack propagation but contributes to an increase in limiting stress for the microcrack initiation.