文章信息/Info

Title:

Influence Factors and Research Progress of Dwell Fatigue for Titanium Alloy

作者:

史棟剛; 徐小嚴; 吳雨; 齊英誠

（中國航發商用航空發動機有限責任公司設計研發中心，上海 201108）

Author(s):

SHI Donggang; XU Xiaoyan; WU Yu; QI Yingcheng

(R&D Center, AECC Commercial Aircraft Engine Co., Ltd., Shanghai 201108, China)

關鍵詞:

鈦合金; 壽命評估; 保載疲勞; 機理; 顯微組織; 保載時間

Keywords:

titanium alloy;  life assessment;  dwell fatigue;  mechanism;  microstructure;  dwell time

DOI:

10.7502/j.issn.1674-3962.201905040

文獻標志碼:

A

摘要:

鈦合金由于其優異的比強、蠕變及疲勞等綜合性能，在航空發動機壓氣機盤等關鍵轉動件中得到廣泛的應用。但近年來的研究發現，采用傳統的三角波或正弦波循環疲勞壽命評估方法可能會高估部分鈦合金在真實運行條件下的疲勞壽命，引發嚴重的安全事故。保載疲勞通常表現為低于200 ℃時，在疲勞峰值應力保持加載一段時間，壽命相比傳統的循環低周疲勞出現大幅降低。此外，裂紋通常萌生于亞表面，較難在零件服役過程中被有效檢測，嚴重危害航空發動機的安全性和可靠性。綜述了近年來國內外在鈦合金保載疲勞產生機理，H元素含量、顯微組織、加載條件、保載時間等因素影響保載疲勞方面的研究進展，并探討了鈦合金保載疲勞的預防及研究發展方向。

Abstract:

Titanium alloy is widely used in critical rotating components of aero engine such as compressor discs due to its excellent comprehensive properties such as high strength-density ratio, good creep and fatigue properties,etc. However, recent research found that the traditional life assessment method for some titanium alloys by low cycle fatigue test under triangular or sine wave mode is likely to overestimate the fatigue life in real operation condition, which may cause serious accident. Dwell fatigue shows significant lifetime reductions under 200 ℃ with hold periods at the peak stress of the cyclic loading compared to standard continuous low cycle fatigue. Moreover, crack usually initiates from the subsurface, which is hard to be detected during service and severely detrimental to the fly safety and reliability. This paper introduces both domestic and foreign researches on mechanism of titanium dwell fatigue, influences of hydrogen content, microstructure, load condition and dwell time on the behavior of dwell fatigue. Then a preventive action with future development is discussed.