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本文研究了经不同热处理获得的双相钢的显微组织特征及其对拉伸性能的影响。结果表明,铁素体的相硬化和马氏体的相软化现象的存在是双相钢的一个重要的组织特征;双相钢的强度除主要决定于马氏体含量外,还随马氏体岛长度直径比的增大而升高;用纤维复合材料混合律来估价不同组织状态的双相钢强度偏差均较大。 相似文献
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以CP980钢、DP980钢、QP980钢为研究对象,采用单轴拉伸试验并结合数字图像相关技术,研究了组织特征对980 MPa级先进超高强钢单轴拉伸行为以及全局、局部成形性的影响。结果表明:QP980钢由马氏体、铁素体、残余奥氏体组织组成,在均匀变形阶段奥氏体相变产生的相变诱导塑性效应使该钢具有最优的全局成形性,但是新生马氏体相与其他相的硬度差较大,导致其局部成形性最差并形成准解理断裂;DP980钢由铁素体和马氏体组织组成,其强化机制以马氏体硬相强化和铁素体位错强化为主,全局成形性居中,同时因铁素体和马氏体之间具有一定的协调变形能力,其局部成形性较好,断裂形式主要为韧性断裂;CP980钢为铁素体、贝氏体、马氏体的多相组织,各相硬度差小,协调变形能力较强,局部成形性最好,断裂形式为韧性断裂。 相似文献
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将X80管线钢加热到奥氏体化温度以上(920℃)并保温7min后,在不同冷却介质(质量分数10%NaCl溶液、自来水、机油、空气,冷却速率依次降低)中冷却,研究了其显微组织和力学性能。结果表明:随着冷却速率的降低,试验钢的强度和硬度降低,塑性增大,冲击功先增大后减小;在较高速率下冷却(NaCl溶液和自来水)后,组织中生成了贝氏体铁素体和少量马氏体板条,马氏体板条内有大量位错结构和少量碳化物,试验钢具有高的强度和低的变形能力;在较低速率下冷却(空气)后,组织中形成了多边形铁素体、贝氏体铁素体和少量块状马氏体-奥氏体组织,试验钢的强度和冲击韧性较低;在适中冷却速率下冷却(机油)后,组织中形成了贝氏体和铁素体的双相组织,多位向分布的细小贝氏体和邻近贝氏体的高密度位错铁素体使得试验钢具有良好的综合力学性能和较高的抗大变形能力。 相似文献
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双相不锈钢各组相循环变形行为的纳米压痕试验和有限元表征方法研究 总被引:1,自引:1,他引:0
对双相不锈钢的奥氏体相和铁素体相,分别开展了不同加载模式(接触载荷和压入位移)和不同加载波形下的单向、循环纳米压痕试验,对比分析了两相的基本力学性能和压痕循环变形行为的演化规律。基于压痕试验结果和修正ABDEL-KARIM-OHNO非线性随动硬化准则的弹塑性本构模型,提出一套双相不锈钢奥氏体相和铁素体相的塑性和循环塑性行为的本构模型参数表征方法。通过对微结构代表性体积单元整体拉伸和循环变形行为进行模拟,并与宏观试验结果对比,验证了参数表征方法的合理性。研究结果表明,铁素体相的强度、硬度和抗棘轮变形的能力均高于奥氏体相,两相之间通过晶界产生一定的交互作用;在接触载荷控制的循环加载条件下,奥氏体相与铁素体相均产生明显的压痕棘轮现象,且载荷水平越高压痕棘轮变形程度越大;所发展的本构模型参数表征方法可为研究多相材料各组相、小体积材料的循环变形行为提供借鉴和参考。 相似文献
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基于Voronoi和概率分布理论,提出材料微观晶相建模方法及其实现流程,建立微观晶相可视化几何模型。通过将微观晶相生成系统和ABAQUS有限元软件相结合,实现了基于微观晶相建模的双相钢有限元仿真,仿真中单相铁素体及马氏体均采用理想弹塑性材料模型,同时,以延性损伤模型模拟材料的破坏行为。以该仿真模型为基础,建立一系列不同晶粒尺寸、不同马氏体体积分数的双相钢微观晶相仿真模型,进行双相钢吸能特性研究,研究表明虽然双相钢吸能量随晶粒尺寸的不同略有差异,但总体均随马氏体体积分数的增加呈现先上升后下降的趋势,最优吸能时双相钢中马氏体体积分数均在2%~5%范围内。实现了双相钢微观尺度下的吸能研究,为轻量化汽车车身安全件的选材提供指导。 相似文献
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本文研究了 30CrMnSiA钢中马氏体(M)+铁素体(F)+贝氏体(Bm)+残留奥氏体(AR)纤维状多相复合组织以及M+F纤维状双相组织对抑制可逆回火脆性的影响,并与该钢常规调质态进行了对比,结果表明:纤维状多相复合组织和双相组织能明显抑制可逆回火脆性。该类复合组织使回火脆化的断裂机制由沿晶断裂改变为韧窝加部分窄条形准解理断裂。 相似文献
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根据球铁断裂过程中石墨及石墨-基体界面的微观力学行为,对球铁组织进行优化设计.以强相(马氏体)或强韧相(奥氏体-贝氏体组织)环包围石墨,基体组织为马氏体或奥氏体-贝氏体组织,加上适量的铁素体,并通过快速加热短时保温后淬火或等温淬火获得.实验结果表明,优化组织球铁具有很高的强韧性.采用扫描电镜动态拉伸观察优化组织球铁断裂过程,发现微裂纹在石墨-基体界面萌生并沿界面扩展,马氏体环或奥-贝环阻碍界面裂纹的萌生与扩展,基体中的硬相和软相分别提高球铁的强度和韧性,这些都有利于提高优化组织球铁的强韧性. 相似文献
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《Wear》1987,119(3):369-390
While the importance of fatigue failure is well established in rolling systems, the evidence for a correlation of fatigue with sliding wear is less convincing. McEvily has reported striking differences in the fatigue properties of two dual phase steels, one containing martensite islands in a ferrite matrix (type A) and one containing ferrite islands in a martensite matrix (type B). We have examined the sliding behavior of these same materials in vacuum and in air for various sliding distances. The pin-on-disk tests included self-mated pairs and tests with molybdenum as a counterface. Post-test analysis included the use of microhardness testing, scanning electron microscopy (including local chemical analysis) and X-ray diffraction analysis of the wear surfaces, sample cross-sections and wear debris. Transitions from low to high friction were associated with transfer processes and mechanical mixing. The wear rates of the type A and B samples were similar in vacuum. However, in air, the wear rates of the type B samples were increased by about 100 times. The lack of correlation with fatigue properties is not yet understood. Any of the following could be responsible: short crack (initiation) phenomena; large local stress intensities; surface material associated with transfer. 相似文献
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M. B. Rigmant 《Russian Journal of Nondestructive Testing》2018,54(2):108-120
The current methods for evaluating the phase composition of austenitic steels that, in addition to austenite, may also contain the phase of ferrite or martensite or both are considered. The possibilities offered by destructive and nondestructive testing techniques are compared. 相似文献
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基于流变学理论的TRIP600钢本构模型研究 总被引:1,自引:1,他引:0
相变诱发塑性(Transformation induced plasticity,TRIP)钢在成形过程中容易发生开裂,主要是由于发生残余奥氏体向马氏体的转变,导致外力与变形不协调。其力学行为不仅有传统的弹性变形和塑性变形,还表现出与时间相关的黏性性质,因此在对其进行本构建模时有必要考虑时间因素对变形行为的影响作用。利用流变模型既可以通过不同构件的组合准确、合理地描述TRIP钢的软、硬相性质,还可以通过各个构件弹性、塑形及黏性系数的变化与组合描述TRIP钢在变形过程中残余奥氏体向马氏体转变的行为特性,即TRIP效应。本文基于流变学理论,对TRIP600的流变学本构模型进行研究和探讨,并最终建立TRIP600分别在蠕变和松弛试验条件下统一的本构方程。 相似文献
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M. K. Korkh M. B. Rigmant D. I. Davydov D. A. Shishkin A. P. Nichipuruk Yu. V. Korkh 《Russian Journal of Nondestructive Testing》2015,51(12):727-737
Three-phase chromium–nickel steels, which contained ferrite, austenite, and martensite (the α' phase that arises after a cold deformation) phases were investigated. The objective of this study was the refinement of the technique of magnetic nondestructive testing of the percentages of the phases in a three-phase material, which was developed by the authors. 相似文献
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The influence of hydrogen on the microstructure of two types of austeno‐ferritic duplex stainless steel (Cr26‐Ni6 model steel and Cr22‐Ni5‐Mo3 commercial steel), each of them after two thermo‐mechanical treatments, was investigated. The aim of this study was to reveal microstructural changes appearing during the hydrogen charging and particularly to clarify the occurrence of phase transformations induced by hydrogen. The specific microstructural changes in the ferrite (α) and austenite (γ) of both types of steel were observed. A strong increase of dislocation density was noticed in the α phase. In the case of model steel, longer hydrogen charging times led to significant ferrite grain refinement. In the commercial steel, the strips and twin plates appeared in the ferrite after hydrogenation. The appearance of stacking faults was revealed in the γ phase. The martensite laths appeared in austenite after longer hydrogenation times. It seems that the microstructural changes gave rise to the formation of microcracks in the α and γ phases as well as on the α/γ interphase boundaries. 相似文献