刘丹梅
,
杨为奉
,
姚枚
,
夏月波
,
郑瑞琪
,
胡宏军
,
李宏运
材料研究学报
通过两种Al 合金表面处理方法及水煮老化处理,得到了不同界面结合状态的玻璃纤维-Al 混杂复合层板,进行了层板层间剪切强度和疲劳裂缝扩展试验,研究了界面结合强度对层板疲劳行为的影响。试验发现,当界面结合强度较高时,层板的疲劳裂缝扩展速率较低,伴随疲劳裂缝扩展而产生的脱层破坏区尺寸较小,脱层破坏发生在树脂层与增强纤维之间;界面结合强度较低时,层板的疲劳裂缝扩展速率较高,脱层区尺寸较大,脱层破坏发生在Al 层和树脂层之间。
关键词:
层板
,
interlaminar strength
,
fatigue crack propagation
,
delamination
K.M. Chang(Department of Mechanical and Aerospace Engineering
,
West Virginia University
,
P.O. Box 6160
,
Morgantown
,
WV 26506
,
USA Manuscript received 26 August 1996)
金属学报(英文版)
P/M superalloy disks obtain their final strength by appropriate heat treatments; the maximum attainable strength depends on the rapid cooling rate from the solution annealing. A rapid quench of a large disk forging can cause two problems, surface cracking and shape distortion.In the past,many attempts employ the finite element code to model and to predict temperature evolution and induced stress distribution in a large turbine disk. The major difficulty was the correct description of alloy behavior; particularly the thermomechanical properties and the failure criteria of material during the cooling. High temperature fatigue resistance is always the key requirement for disk materials. New methodology of residual life management emphasizes the initiation as well as the propagation of the cracks developed under the service conditions. One of major challenges to P/M superalloys is the time-dependent behavior of fatigue cracking, which relates to the well-known SAGBO (stress-assisted grain boundary oxidation) phenomenon.A great effort has been done to understand the micro-mechanism of time-dependent fatigue crack propagation resulted in the second generation of P/M superalloys. Further improvement on temperature capability of disk alloys at rim area may lead to the idea of dual-property disks.Different grain structures at different portions of a large disk are possible,as the property requirements for different locations are different. This goal is achievable if the thermal history at specific disk locations can be controlled to develop desirable microstructures and properties.Some suggestions on the future direction of research efforts will be discused.
关键词:
:superalloy disk
,
null
,
null
,
null
,
null
,
null
,
null
DENG Rongying ZHOU Aihua JIANG Huaiqing LI Chunxiu Institute of Mechanics
,
Academia Sinica
,
Beijing
,
ChinaZHANG Liqing
,
SUN Yutian Beijing Institute of Engineering
,
Beijing
,
China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A219—A225
,
Associate Profes sor
,
Institute of Mechanics
,
Academia Sinica
,
Beijing
,
China
金属学报(英文版)
The effect of pearlite interlamellar spacing(d)from 0.31 to 0.77 μm of T8 steel on fatigue crack propagation near threshold has been investigated at different stress ratios(R).The closure stress intensity factor(K_(cl)),the threshold value(ΔK_(th))and crack tip opening dis- placement range(ΔCOD)were measured.The results show that pearlite interlamellar spac- ing in this range has no effect on K_(cl),but has effect on the threshold value in low stress ratio. The threshold value is higher for materials with larger interlamellar spacing.No matter what the stress ratio is,during the propagation near threshold,the propagation rate will be the same,provieded the crack tip opening displacement range is the same. Metallurgical examinations were also carried out to show that the crack propagation path is sensitive to mierostructure.The crack always propagates along either boundary of pearlite colony or ferrite lamellar in pearlite.
关键词:
pearlitic steel
,
null
,
null
,
null
PEI Hongxun Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
Based on the experimental study of complex biaxial mode Ⅰ fatigue crack growth and the discussion on Von Mises'theory,a new approach is proposed for correlating crack propaga- tion rate under both in-phase and out-of-phase biaxial stress cycling.The results emphasize the contribution of plasticity to fatigue crack growth.
关键词:
biaxial stress
,
null
,
null
,
null
祝力伟
,
王新南
,
朱知寿
,
刘德林
,
俞汉清
稀有金属材料与工程
研究了双态组织、片层组织TC4-DT钛合金在近门槛区的疲劳裂纹扩展行为,通过扫描电镜观察裂纹扩展路径及断口微观特征,研究了等轴初生α相含量对TC4-DT钛合金在近门槛区疲劳裂纹扩展速率的影响,讨论了TC4-DT钛合金的疲劳裂纹扩展行为和断裂方式.结果表明:随着等轴初生α相含量的降低,TC4-DT钛合金在近门槛值区的da/ dN-△K曲线逐渐向下偏折,裂纹扩展速率明显降低,在Paris区出现转折点现象且转折点对应的△Kt值逐渐增大;片层组织在近门槛区的裂纹扩展路径曲折,疲劳裂纹扩展速率显著降低,表现出更好的损伤容限性能.
关键词:
损伤容限
,
TC4-DT钛合金
,
显微组织
,
近门槛区
,
疲劳裂纹扩展
李行志
,
胡树兵
,
肖建中
,
王亚军
,
李清华
,
籍龙波
航空材料学报
doi:10.3969/j.issn.1005-5053.2010.1.010
对TA15电子束焊接接头的熔凝区和热影响区的显微组织、硬度、疲劳裂纹扩展速率、以及疲劳断口形貌进行了研究.结果表明:熔凝区的显微组织主要为粗针状α′马氏体组织,热影响区组织为α′马氏体组织+条片状的α相和β相,由接近熔凝区组织向母材组织过渡.母材的硬度较低,熔凝区平均硬度最高,热影响区的硬度介于两者之间.疲劳裂纹扩展速率高低与其显微组织密切相关,含塑性较好的片状α相较多的热影响区比熔凝区有较高的裂纹扩展抗力.
关键词:
TA15钛合金
,
电子束焊接
,
显微组织
,
疲劳裂纹扩展
谢孝昌
,
柴志刚
,
李权
,
汤春峰
,
赵振业
航空材料学报
doi:10.11868/j.issn.1005-5053.2015.5.008
采用扫描电镜对直接时效(DA) GH4169合金在室温和650℃下的光滑(Kt=1)和缺口(Kt=3、4)旋转弯曲疲劳试样断口进行了研究.研究表明,DAGH4169合金室温旋转弯曲疲劳光滑(Kt=1)试样断口在大应力状态下具有多源疲劳断裂特征,在低应力状态下则具有单源疲劳断裂特征,且疲劳裂纹均起始于表面加工缺陷处.DAGH4169合金室温旋转弯曲疲劳缺口(Kt=3,4)试样均起源于缺口根部的加工缺陷处,在实验载荷下均呈现多源疲劳断裂特征.DAGH4169合金650℃旋转弯曲疲劳光滑(Kt=1)试样断口呈单源疲劳断裂特征,起始于外表面加工缺陷处.DAGH4169合金650℃旋转弯曲疲劳缺口(Kt=3,4)试样均起源于缺口根部加工缺陷处,呈多源疲劳断裂特征.所有观察试样随疲劳载荷的逐渐降低,疲劳源区逐渐平滑,疲劳扩展逐渐充分,瞬断区面积逐渐减小,瞬断区的偏心距离逐渐增大.
关键词:
DAGH4169
,
疲劳断口
,
疲劳源
,
疲劳扩展
刘铭
,
张坤
,
戴圣龙
,
黄敏
,
伊琳娜
航空材料学报
doi:10.3969/j.issn.1005-5053.2014.1.013
采用轴向加载疲劳试验方法,研究了航空用2124-T851铝合金板材不同取样方向、试样形式以及实验应力比下的疲劳性能;并通过金相显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)分析了该合金的显微组织和疲劳断口形貌.结果表明:2124-T851铝合金板材具有良好的耐疲劳损伤性能,疲劳极限随应力比的增加而增大;缺口的存在大大降低了材料的疲劳极限,光滑试样(Kt=1)的疲劳极限大约是缺口试样(Kt=3)的2倍;板材横向疲劳极限高于纵向疲劳极限,且应力比越小差异越大.断口形貌具有典型的疲劳断口特征,由疲劳源区、疲劳裂纹稳定扩展区和快速断裂区三部分组成,裂纹萌生一般位于表面夹杂或缺口等缺陷引起的应力集中处.
关键词:
铝合金
,
疲劳性能
,
疲劳裂纹扩展
,
断口形貌
黄澳
,
陈吉
,
张啸尘
,
耿越
,
杨斌
钢铁研究学报
doi:10.13228/j.boyuan.issn1001-0963.20160025
采用光学显微镜、扫描电镜、EDS能谱分析和力学性能测试等方法，研究了固溶处理对2205双相不锈钢显微组织与疲劳裂纹扩展规律的影响。结果表明：与原始热轧态相比，在950~1150℃范围固溶处理的试样的疲劳裂纹门槛值显著提高，稳态裂纹扩展速率均有所减小。在950℃固溶处理时，组织中析出少量的σ相，试样的稳态裂纹扩展速率显著降低；随着固溶温度的升高，组织中α相含量逐渐增加，σ相溶解，试样的稳态裂纹扩展速率的变化呈现为先增大后减小的趋势；当固溶温度达到1150℃时，组织中α相含量最高且两相组织明显粗化，试样的稳态裂纹扩展速率达到最小，呈现出最高的抗疲劳裂纹扩展能力。固溶处理引起σ相的析出与溶解、α相含量的增加及组织粗化是引起2205双相不锈钢试样疲劳裂纹扩展性能非单调变化的原因。
关键词:
双相不锈钢
,
固溶处理
,
显微组织
,
疲劳裂纹扩展
