DENG Rongying ZHOU Aihua JIANG Huaiqing LI Chunxiu Institute of Mechanics
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Academia Sinica
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Beijing
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ChinaZHANG Liqing
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SUN Yutian Beijing Institute of Engineering
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Beijing
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China [Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A219—A225
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Associate Profes sor
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Institute of Mechanics
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Academia Sinica
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Beijing
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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
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null
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null
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null
X. Zhang
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C.X. Wang
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X.M. Liu
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Q.N. Shi
金属学报(英文版)
The microstructure evolution of different cold rolling reductions （from 0 to 81.6%）is studied by SEM (scanning electron microscopy) and TEM (transmission electron microscope). The study showed that the orientation multiplicity of pearlitic lamellas resulted in inhomogeneous deformation of different pearlitic lamellas, and with the increase of reduction, the microstructure underwent a course of "homogeneity → inhomogeneity → homogeneity". The result of XRD (X-ray diffraction) analysis indicated that cementite did not decompose and dissolve into ferrite; the results of the mechanical property test suggested that the relationship between Rp0.2 (yield strength) and ε (true strain) is in good agreement with Hollomon relationship. With the equation Rp0.2 = 1465ε0.18, the yield strength of the steel in different reductions could be well predicted.
关键词:
cold rolling
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null
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null
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null
梁宇
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余凌锋
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梁益龙
材料热处理学报
以SWRS82B钢为研究对象,制定热处理工艺:将试样奥氏体化后在低温盐槽停留短时间后马上进入高温盐槽等温,目的是增加珠光体转变过冷度,提高珠光体形核率,减小珠光体团尺寸,从而探索高碳珠光体钢力学性能与显微组织尺寸之间的关系.结果表明,珠光体钢强度指标主要由珠光体片层间距决定.晶粒尺寸明显影响塑性指标,晶粒尺寸越小塑性指标越高,而当晶粒尺寸相近时,珠光体团尺寸越细小断面收缩率越高.
关键词:
珠光体钢
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片层间距
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晶粒尺寸
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团尺寸
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拉伸性能
杨帆
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蒋建清
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方峰
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王燕
稀有金属材料与工程
采用扫描电子显微镜和X射线衍射技术,分别研究了珠光体钢在冷拉拔过程中的组织结构和残余应力演化.随着拉拔应变量的增大,珠光体团逐渐转向拉拔方向.影响珠光体钢丝屈服应力和抗拉强度的关键因素是珠光体片层间距,它们之间满足Hall-Petch公式,通过拉伸试验求得其中k值为567.4 kN·m-3/2.钢丝残余应力的X射线衍射测量结果表明,随着应变量增加,钢丝的应力增大,这与拉拔过程中的加工硬化有关.
关键词:
拉拔
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珠光体钢
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Hall-Petch关系
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残余应力
石祥虎
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陈豫增
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张昆华
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刘峰
材料热处理学报
以真应变量为3的冷拔纳米珠光体钢丝为研究对象,对钢丝在不同退火温度下的拉伸力学性能热稳定性进行了研究.发现,该钢丝力学性能的热稳定性可维持到523 K.基于实验结果及相关理论模型,分析了冷拔纳米珠光体钢丝力学性能热稳定性的微观控制机制.结果表明,钢丝力学性能的热稳定性主要受到铁素体中的空位团浓度演化、位错密度演化、碳元素与位错的交互作用等因素的共同控制.当退火温度高于523 K时,铁素体中空位团的泯灭、位错密度的降低及碳元素对位错钉扎效应的消失,共同导致了钢丝的力学性能的急剧退化.
关键词:
珠光体钢
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纳米材料
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微观组织
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力学性能
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热稳定性
魏泽民
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梁宇
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梁益龙
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熊虎
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韦贤毅
材料热处理学报
以珠光体钢为研究对象,在不同盐浴温度下等温获得不同特征的珠光体组织.进行了力学性能测试与准静态断裂韧性(J0.2BL)测试,在扫描电子显微镜(SEM)下观察了微观组织与裂纹扩展路径.研究结果表明,珠光体片层间距与铁素体量对断裂韧性具有显著影响,裂纹扩展阻力由珠光体片层间距以及先共析铁素体含量共同决定,根据不同组织对裂纹扩展阻力的贡献值珠光体钢裂纹扩展总阻力可用表达式δ(SUM) =k'δ(P) +kδ(F)来进行描述,随着等温温度的增加,珠光体片层间距与先共析铁索体量增加,珠光体钢裂纹扩展总阻力呈先上升后下降的趋势,与J0.2BL实验结果具有一致的趋势.
关键词:
珠光体钢
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断裂韧性
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裂纹扩展
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索氏体化率
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片层间距
