材料期刊网，材料期刊，材料类期刊，材料期刊投稿

采用紧凑拉伸试样进行恒载和降K控制的拉--拉疲劳实验, 研究了喷射沉积SiC_p/Al-7Si复合材料及其基体的疲劳裂纹扩展行为. 通过金相显微镜和扫描电镜观察了复合材料及其基体的组织和疲劳裂纹扩展形貌, 研究了SiC颗粒对复合材料疲劳裂纹扩展机制的影响. 结果表明: 复合材料在任何相同的ΔK水平下其抗疲劳裂纹扩展能力优于基体材料, 并表现出较高的疲劳门槛值. 其原因是复合材料中裂纹裂尖遇到增强颗粒时, 裂纹发生偏转, 特别是SiC颗粒自身微裂纹萌生有效降低了裂纹尖端的应力强度因子, 复合材料的裂纹闭合效应也随之增大. 去除裂纹闭合效应的影响, 当有效应力因子ΔK_eff作为裂纹扩展的驱动力时, 复合材料的裂纹扩展速率却高于基体.

关键词: Al-Si合金 , SiC particle , composite , spray deposition , fatigue crack growth , crack closure

疲劳断裂过程中渗碳层残余奥氏体的转变

井晓天 , 楼秉哲 , 谷臣清 , 沈福三

金属学报

研究了20CrNiMo钢微氮渗碳层中残余奥氏体的形态,及其在疲劳断裂过程中的转变和作用。结果表明:渗碳层残余奥氏体有薄膜状和块状两种形态,由于界面取向的影响,疲劳裂纹更易于穿过块状奥氏体,促使其发生应变诱发马氏体相变。在疲劳断裂过程中,裂纹面附近的残余奥氏体大部分转变成马氏体,这种转变是在断裂瞬间发生的,与疲劳力学条件无关。转变所引起的体积膨胀增强了裂纹闭合效应。相变诱发闭合是渗碳表层高碳区疲劳裂纹扩张行为的主要因素之一。

关键词: 残余奥氏体 , fatigue crack growth , strain induced martensite transformation , phase transformation induced crack closure

3.5%NaCl溶液对铝合金疲劳裂纹扩展特性的影响

刘绍伦 , 李谦 , 欧阳辉 , 岳俊文 , 罗安民

腐蚀学报（英文）

对高强铝合金7050—T7451在模拟海水(3.5%NaCl溶液)的疲劳裂纹扩展特性进行了试验研究结果表明,3.5%NaCl溶液加速了7050—T7451铝合金的疲劳裂纹扩展速率da/dN.考虑应力比影响的有效应力强度因子面ΔKefT可以满意地表征不同环境中的的da/dN.裂纹面上的腐蚀产物较薄,对疲劳裂纹闭合的影响可以忽略不计.

关键词: 铝合金 , fatigue crack growth , crack closure , 3.5% NaCl solution , null

双轴加载条件下疲劳裂纹扩展的研究

裴鸿勋

金属学报

在双轴加载条件下对Ⅰ型疲劳裂纹扩展进行了研究。载荷范围从0.08σ_s到0.71σ_3,包括比例加载和非比例加载。基于对Von Mises理论的讨论,提出一个新的力学参数。双轴加载条件下的弹塑性参数P成功地描述了双轴比例加载和非比例加载下的疲劳裂纹扩展。

关键词: 双轴加载 , fatigue crack growth , nonproportional loading , strain energy density

Effect of Pre-loading on Short Fatigue Crack Growth at a Notch

XU Kewei HE Jiawen ZHOU Huijiu ** Research Institute for Strength of Metals , Xi'an Jiaotong University , Xi'an , 710049 , China+ To whom correspondence should be addressed

材料科学技术（英文）

Results indicate that under cyclic tension the growth rate of short fatigue crack from notch root will be lowered greatly by tensile pre-loading,but only a little change by compressive pre-loading. The effect of tensile pre-loading will decrease with the increase of stress ratio.The variation of short fatigue crack growth rate is related to the residual stress distribution around notch root.

关键词: fatigue crack growth , null , null , null

疲劳裂纹扩展的非比例过载效应

高桦 , 陈友萱 , 李明 , 陈德海

金属学报

本工作研究了比例(Ⅰ型)过载及非比例(复合型)过载对常幅Ⅰ型疲劳裂纹扩展的影响。结果表明:Ⅰ型过载所引起的裂纹滞后扩展效应远较复合型为强。因此,在估算疲劳寿命时将零、构件实际承受的过载(大都为非比例过载)简单地当作比例过载处理,可能会过高地估计寿命,带来不安全因素。文章从Ⅰ型及复合型过载所引起的裂纹钝化、裂端塑性区的形状、尺寸及裂纹闭合等方面讨论了它们对裂纹扩展滞后效应的影响。

关键词: 非比例过载 , fatigue crack growth , mixed mode loading

玻璃纤维-Al 混杂复合层板的疲劳裂缝扩展行为

刘丹梅 , 曲伟 , 杨为奉 , 张瑞平 , 夏月波

材料研究学报

本文研究了一种新型结构复合材料玻璃纤维-Al 混杂复合层板(Glass Aluminum Laminates,GLALL)在不同外载荷作用下的疲劳裂缝扩展行为,以及疲劳破坏规律。试验发现,由于未断高强度纤维对裂缝的桥接作用降低了裂缝尖端的有效应力场强度因子,GLALL 的疲劳裂缝扩展速率远低于单一Al 合金。伴随Al 合金层内疲劳裂缝的扩展,GLALL 疲劳裂缝附近区域会产生脱层破坏,脱层区宽度随外加载荷增大而增大。脱层区宽度越小,纤维对疲劳裂缝的桥接作用越强。

关键词: 复合层板 , fatigue crack growth , delamination

ON FATIGUE CRACK PATH DEVIATION AT ELEVATED TEMPERATURE IN ELECTRON BEAM REPAIRED WELDMENTS OF TURBINE DISK

H.Q.Zhang

金属学报(英文版)

Fatigue crack growth behaviors in electron beam weldments of a nickel-base superalloy are. studied. The objective of this paper is to discuss effects of the inhomogeneity of mechanical performance on fatigue crack growth (FCG) rate and crack path deviation (CPD). The base metal served in a turbine disk of aerospace engine was selected to fabricate bead-on-plate weldments by using electron beam welding. Some wedge-type opening loading specimens, notched in three different zone of weld metal, HAZ and base metal, were employed and performed fatigue crack growth tests at 650℃. The results show that the fatigue crack growth of electron beam welded joints is instable due to the influence of mechanical heterogeneities. Owing to the crack deviation at the weld metal and heat-affected-zone (HAZ), the effective growth driving force at the tip of fatigue crack was reduced with the reduction of the effective stress intensity factor (SIF) which finally causes fatigue crack rate decrease. Fatigue crack was strongly affected by size and the symmetrical characteristics of the plastic zone at the crack tip, which means that the integrity of the welded structure containing the fatigue crack mainly depended on the toughness of the low strength zone.

关键词: fatigue crack growth , null , null

CRACK GROWTH BEHAVIOR IN TITANIUM ALLOY TC11AT ROOM AND HIGH TEMPERATURES

Author H.F. Huang and S.L. Liu Laboratory of Material Mechanical Properties , Beijing Institute of Aeronautical Materials (BIAM) , Beijing 100095 , China Manuscript received 18 October 1998

金属学报(英文版)

This paper presents some new results of a research on the fatigue crack propagation (FCP) behavior in the titanium alloy TC11. Crack propagation tests were carried out at room temperature by center cracked tension (CCT) specimens under three stress ratios of R=0, 0.5, -1, and at 400 by compact tension (CT) and single edged specimens under stress ratios of R=0.1 and -1, respectively. The crack growth rates were compared by using stress intensity factor and effective stress intensity factor. The results show that the effects of stress ratio and ambient temperature on crack growth rates decreased if they were correlated by using the effective stress intensity factor.

关键词: fatigue crack growth , null , null

Fatigue Crack Growth of Al-Li Alloy 2091 in 3.5% NaCl Solution and at 130℃

HE Shiyu WANG Zhongguang LI Qingjian ZHANG Yun FENG Xiaozeng State Key Laboratory for Fatigue and Fracture of Materials , Institute of Metal Research , Academia Sinica , Shenyang , 110015 , ChinaDept.of Materials Science and Engineering , Harbin Institute of Technolo

材料科学技术（英文）

A study has been made of the fatigue crack growth in an Al-Li alloy 2091 in 3.5%NaCl solu- tion and at an elevated temperature of 130℃.The aging and environmental effects on the crack growth behaviour were examined.It is shown that the fatigue crack growth resistance decreases with aging.The specimen with underaged structures shows the highest resistance to fatigue crack growth due to more deflected crack paths and the resulting high crack closure levels.As compared to laborato- ry air,both 3.5% NaCl solution and elevated tem- perature of 130℃ cause an increase of near-thresh- old crack growth rates and a decrease of threshold levels.The elevated temperature is more effective. The effect of elevated temperature is mainly due to the precipitate coarsening which results in an enhancement of slip irreversibility.Hydrogen embritttlement is supposed to be responsible for the degradation of fatigue crack growth resistance in 3.5%NaCl solution

关键词: fatigue crack growth , null , null

材料期刊网

喷射沉积SiC_p/Al-7Si复合材料的疲劳裂纹扩展

疲劳断裂过程中渗碳层残余奥氏体的转变

3.5%NaCl溶液对铝合金疲劳裂纹扩展特性的影响

双轴加载条件下疲劳裂纹扩展的研究

Effect of Pre-loading on Short Fatigue Crack Growth at a Notch

疲劳裂纹扩展的非比例过载效应

玻璃纤维-Al 混杂复合层板的疲劳裂缝扩展行为

ON FATIGUE CRACK PATH DEVIATION AT ELEVATED TEMPERATURE IN ELECTRON BEAM REPAIRED WELDMENTS OF TURBINE DISK

CRACK GROWTH BEHAVIOR IN TITANIUM ALLOY TC11AT ROOM AND HIGH TEMPERATURES

Fatigue Crack Growth of Al-Li Alloy 2091 in 3.5% NaCl Solution and at 130℃

出版年份

刊物分类

相关作者

相关热词