韩恩厚
,
韩玉梅
,
郑宇礼
,
柯伟
金属学报
在理论分析裂尖局部应变、应变速率及溶解速度的基础上、实验测定了低合金钢ZG20SiMn,SM50B—Zc的腐蚀疲劳裂纹扩展速率,并随着裂纹的扩展测定了裂纹内和裂纹尖端的pH值和金属电极电位、指出降低频率和增加应力比所导致的腐蚀疲劳裂纹扩展速率的增加部分主要来自于氢脆的加速作用
关键词:
腐蚀疲劳
,
stress ratio
,
frequency
,
crack growth
,
steel ZG20SiMn steel SM50B-Zc
,
null
S.A.Shipilov
中国腐蚀与防护学报
针对高强度低合金钢、钛合金和镁合金进行了腐蚀疲劳裂纹的扩展FCG、外加电压对于腐蚀疲劳裂纹扩展速率的影响以及断裂表面的研究。在外加电压对于腐蚀疲劳裂纹扩展速率影响的研究过程中，在一段时间内发生极化，可以根据此期间内的开路电压记录裂纹扩展速率，并测量极化情况下的裂纹增长速率。由于裂纹扩展测量技术的进步，测量的时间很少超过300s，这使观测非独立模式阴极极化对于腐蚀疲劳裂纹扩展速率的影响成为可能。当最大应力强度（Kmax）超过给定材料--溶液组合的特定临界特征值时，阴极极化会加速裂纹的扩展。当Kmax低于临界值，而所有其他条件（试件、溶液、pH值、载荷频率、应力比率、温度等）不变时，同样的阴极极化会妨碍裂纹扩展，或者对于裂纹扩展无影响。断口显微分析结果显示，阴极极化下加速裂纹的扩展是由于氢致腐蚀(HIC)。因此，根据氢致腐蚀机理以及KHIC和△ KHIC的显示，Kmax的临界值，以及应力范围（△ K）是由相应的腐蚀疲劳裂纹扩展的症状所确定的。当Kmax > KHIC（△ K > △ KHIC）时，腐蚀疲劳裂纹扩展的主要机理是HIC。对于大多数的材料--溶液组合的研究表明，当Kmax < KHIC（△ K < KHIC）时，应力协助扩散在腐蚀疲劳裂纹扩展中起决定性作用。
关键词:
腐蚀疲劳
,
crack growth
,
fracture surface
,
high-strength steels
,
hydrogen-induced cracking
王富岗
,
祝苏明
,
朱世杰
,
任晓民
,
谭毅
,
张俊善
金属学报
在两种不同晶界状态下研究了Fe-Cr15-Ni25合金的蠕变裂纹扩展行为。单相合金的空洞在晶界三叉点处形核,而对晶界上有碳化物析出的合金,空洞在晶界碳化物上形核。晶界碳化物阻碍了空洞的长大和连接,因而大大提高了蠕变裂纹扩展抗力。
关键词:
蠕变
,
crack growth
,
grain boundary carbide
,
cavity
,
Fe-Cr15-Ni25 alloy
臧启山
,
刘慷
,
柯伟
,
郑宇礼
金属学报
本文给出了国产海洋用钢36z焊缝及热影响区在人工合成海水中不同频率的裂纹扩展特征,并与国外同样强度级别的海洋用钢A537焊缝的裂纹扩展率进行了比较。结果表明,在人工合成海水中国产钢焊缝和热影响区低频比高频下的裂纹扩展率分别高3—5倍和4—10倍;国产钢焊缝与A537焊缝的裂纹扩展率基本相当。本文对腐蚀介质下焊缝裂纹扩展规律和断裂特征进行了讨论。
关键词:
焊缝
,
corrosion fatigue
,
crack growth
ZANG Qishan LIU Kang KE Wei ZHU Ziyong Laboratory of Fatigue and Fracture of Sinica
,
Materials
,
IMR
,
China.Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China.
材料科学技术（英文）
The crack growth rates of A537 c1.1 steel and its weld metal have been investigated both in air and in artificial sea water.The effects of stress ratio,frequency,residual stress of welds as well as corrosion products on cor- rosion fatigue crack growth rate have been exa- mined.Some electrochemical reactions occurred during tests and models for describing the cor- rosion fatigue crack growth process in low strength of offshore structural steel were discussed.
关键词:
crack growth
,
null
,
null
Q.J. Zhu
,
Y.H. Chen
,
J. Chen
金属学报(英文版)
With the increasingly use of FRC (fiber-reinforced composite) in urban lifelines, mechanical properties investigation is very important for disaster resistance, especially
the investigation of fatigue properties. Based on the shear-lag model, an usual composite model under cyclic loading is established. According to the Paris formula, the
relationship between interfacial fatigue parameters and the number of cycles is obtained under the cyclic loading. Interfacial fatigue properties of this model and the
growth of the interfacial fatigue crack are analyzed. And the Poisson ratio is considered also.
关键词:
interfacial debonding
,
null
,
null
,
null
,
null
GAO Hongbin
,
Harbin Shipbuilding Engineering Institute Harbin
,
China GAO Hongbin
,
Associate Professor
,
Harbin Shipbuilding Engineering Institute
,
Harbin 150001
,
China
金属学报(英文版)
The corrosion fatigue crack growth and near-threshold characteristics of a medium strength steel HT60 were investigated using compact tension specimens exposed to synthetic sea water. The da/dN-△AK_(eff) relation in air can give a conservative estimation of da/dN-△K relations in sea water. In the case of high R, however, crack growth acceleration at high △K regions appears to be cantrolled by the stress-assisted dissolution. The crack opening stress inlensity factor K_(op) detected by the back-face-strain method is the result of crack surface in contact with the corrosion products and therefore an overestimated value of K_(op) at the crack tip is given.
关键词:
corrosion fatigue
,
null
,
null
,
null
