共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
GAO Hongbin Harbin Shipbuilding Engineering Institute Harbin China GAO Hongbin Associate Professor Harbin Shipbuilding Engineering Institute Harbin China 《金属学报(英文版)》1992,5(7):48-52
The corrosion fatigue crack growth and near-threshold characteristics of a medium strengthsteel 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 relationsin sea water. In the case of high R, however, crack growth acceleration at high △K regionsappears to be cantrolled by the stress-assisted dissolution. The crack opening stressinlensity factor K_(op) detected by the back-face-strain method is the result of crack surface incontact with the corrosion products and therefore an overestimated value of K_(op) at the cracktip is given. 相似文献
3.
Fe—Mn—C合金奥氏体强化对马氏体相变的影响 总被引:3,自引:0,他引:3
测定了5种Fe-Mn-C合金的M_s温度及奥氏体在M_s温度时的屈服强度,结果表明两者成线性关系。还研究了奥氏体固溶强化对马氏体形态的影响,提出存在一个奥氏体强化特征温度T_c,当M_s>T_c时,马氏体形态主要为位错型条状马氏体,当M_s相似文献
4.
PAN Mu XU Zuyao 《金属学报(英文版)》1990,3(3):153-157
The M_s temperature and the yield strength of austenite at M_s temperature have been meas-ured for five Fe-Mn-C alloys.The experimental results show that there is a linear relation-ship between them.The effect of the solution strengthening of austenite on martensitemorphology is also studied.It is pointed out that there is a characteristic temperature T_c inaustenite strengthening.Martensite morphology is mainly of dislocated laths when M_s>T_c,and is mainly of twinned plates when M_s相似文献
5.
R.O.Ritchie Department of Materials Science Mineral Engineering University of California Berkeley CA U.S.A. 《中国有色金属学会会刊》1999,(Z1)
1 INTRODUCTIONFatigueinvolvesthemicrostructuraldamageandfailureofmaterialsunderalternatingloads.Structuralmaterials,however,arerarelydesignedforfatigueresistance.Metallicalloysaregenerallydesignedforstrength,intermetallicsforductility,andceramicsfor… 相似文献
6.
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SiCp/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ΔKeff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. 相似文献
7.
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. 相似文献
8.
HT60高拉力钢在人工海水中的腐蚀疲劳裂纹扩展特性 总被引:1,自引:0,他引:1
对高拉力钢HT60的腐蚀疲劳裂纹扩展特性和门槛值区域特性,采用紧凑拉伸试件在人工海水中进行了实验和研究,结果表明:在空气中的da/dN与ΔK_(cff)关系可以作为在海水中的da/dN与ΔK关系的一个偏保守的预测;在高应力比的高ΔK区域,由于应力诱起溶解促进了裂纹扩展的加速;该裂纹开口应力强度因子K_(op)仅反映了裂纹表面同腐蚀生成物接触的结果,从而导致了K_(op)在裂纹尖端的偏大的估计结果。 相似文献
9.
循环载荷下裂尖形变规律的实验研究 总被引:2,自引:0,他引:2
应用散斑干涉技术,在常幅载荷下对疲劳裂纹扩展过程中的一个循环周期内,不同加载阶段的裂尖应变、裂纹张开位移进行了原位测量,给出了裂纹闭合对裂纹张开位移及裂尖形变的影响规律。结果表明:由于裂纹闭合和残余压应力的存在,疲劳裂尖应变与外加载荷的平方并不成正比,在加载初期,裂纹处于闭合状态,裂尖应变无明显变化,随着载荷的增加,裂纹逐渐由远离裂尖处张开并向裂尖发展,一旦裂纹完全张开,裂尖应变迅速增加,对裂尖应力-应变状态的分析表明,裂尖材料的应力-应变关系类似于光滑试样低周拉压疲劳应力-应变滞后关系。 相似文献
10.
11.
S. Fedosov 《金属学报(英文版)》2000,13(1):40-44
1.IhtroductionStmctureandpropertiesOfsteelsafterlaserprocessing(LP)havebeenstudiedbynumberofresearchers.Inthegreatmajorityofthestudies,specialattentionhasbeenpaidtochangestakingplaceininartensite.Farlessattentionhasbeengiventoretainedaustenitesearch.%tiealmetallo~wasusedalso."Thermo"computerprogramwasemployedforcomputationofthermalcyclep~tersddringlaserprocessing[.'jTh.eXPerimentalmethodsaredescribedinmoredetail[5--8).3.ffesatts3.1QuantityoftheretainedausteniteEffectOfcarbonontherAcontenti… 相似文献
12.
GAO Hua CHEN Youxuan LI Ming Shanghai University of Engineering Science Shanghai ChinaCHEN Dehai Shanghai Dalong Machinery Shanghai China Associate Professor Dept.of Materials Shanghai University of Engineering Science Shanghai China 《金属学报(英文版)》1991,4(1):59-64
The effect of proportional and non-proportional overloading on mode l fatigue crack growthhave been studied,and the influences of crack tip plastic zone,crack tip blunting as well ascrack closure were discussed.Proportional(model I)overloading may cause more seriouscrack growth retardation than non-proportional(mixed mode)overloading.Therefore,forestimating the fatigue life of engineering structures to simplify a real overload which may of-ten be non-proportional as a proportional one is not always safe. 相似文献
13.
14.
15.
Y. Chen X. ChenWuhan University of Science Technology Wuhan ChinaQ.F. Wang G.L. Yuan and. C. Y. LiTechnical Center of Wuhan Iron Steel Co. Wuhan ChinaX. Y. Li Y.X. WangCentral Iron Steel Research Institute Beijing 《金属学报(英文版)》2002,15(4):339-345
The systematic chemical compositions including common C, Si, Mn, Al, and micro-alloying elements of Ti and Nb were designed for high volume fraction of retained austenite as much as possible. The thermo-cycle experiments were conducted by using Gleeble 2000 thermo-dynamic test machine for finding the appropriate composition. The experimental results showed that chemical composition had a significant effect on retained austenite, and the appropriate compositions were determined for commercial production of TRIP steels. 相似文献
16.
17.
18.
19.
H.C.Yang Y.Tu M.M.Yu J.Zhao 《金属学报(英文版)》2004,17(4):597-600
Low cycle fatigue tests and crack growth propagations tests on P91 pipe base metal and its weld joints were conducted at three different temperatures: room temperature, 550℃ and 575℃. The strain-life was analyzed, and the changes in fatigue life behavior and fatigue growth rates with increasing temperature were discussed. The different properties of the base metal and its weld joint have been analyzed. 相似文献