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氮强化高锰奥氏体不锈钢的应变硬化行为 总被引:1,自引:0,他引:1
研究了22Mn-13Cr-5Ni-0.25N钢的应变硬化行为。结果表明:变形初期,形变孪晶的形成降低应变硬化指数;随应变增加,先形成的形变孪晶阻碍位错运动的阻碍其它「111」γ形变孪晶形成,从而提高应变硬化指数,应变硬化指数n与真应变量ε的关系为n=α.ε+b。 相似文献
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为研究冷变形及碳含量对节镍型高氮奥氏体不锈钢应变硬化的影响规律,选取2种碳含量和6种变形量的节镍型高氮奥氏体不锈钢进行拉伸实验,根据实验结果绘制工程应力-工程应变曲线,结合实验结果及微观组织分析,得出结论:高氮奥氏体不锈钢在冷轧过程中,随着变形量增加,屈服强度及抗拉强度均呈现大幅度上升,但伸长率逐渐降低。随着奥氏体晶粒拉长,微观组织中孪晶密度随着变形量的加大而增加,变形孪晶破坏,孪晶在滑移分割作用下呈现条带状。对比不同变形量的冷轧材料拉伸结果,屈强比随冷变形量的增加而增加。在小变形量(10%~20%)时,加工硬化值随着碳含量的增加而减小;当变形量较大时,随着应变量的增加,含碳量高的实验钢表现出更强的加工硬化。 相似文献
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冷轧301L奥氏体不锈钢的变形和应变硬化行为 总被引:5,自引:1,他引:4
研究了SUS301L和CN301L奥氏体不锈钢HT(high tensile,4/4H)和DLT(deadline tensile,1/4H)两个硬化等级冷轧板材的变形和应变硬化行为及其应变诱发α′马氏体转变.所有301L冷轧板拉伸试样近断口处都发生了85%以上的马氏体相变,轧制变形量增加,室温拉伸应变诱发马氏体转变开始的应变减小,但未增加马氏体转变饱和值.CN301L中C和N的含量高于相同硬化等级的SUS301L,导致它们变形和硬化行为不同.C和N的含量较高,对γ相和α′相的固溶强化效果增强,冷轧奥氏体不锈钢无需发生大量马氏体转变就能达到要求的高屈服强度,保证冷轧板材具有较好的塑性和一定的成型能力;此外,形成的应变诱发马氏体中,C和N的固溶度大,硬化效果增强,流变应力上升快,抗拉强度高;C和N含量较高,还增加奥氏体的稳定性,将拉伸过程中应变诱发马氏体转变推迟到较高应变发生,延长应变硬化行为的第二阶段,增强相变增塑效应. 相似文献
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使用Gleeble-3180热模拟力学实验机,采用双道次压缩方法研究了Z2CNN19-10奥氏体不锈钢的高温形变行为。还研究了该钢的静态软化行为。结果表明:随着变形温度的降低,应变速率的增加,变形量的增大,流变应力升高。变形温度较高时,即1050、1150℃,实验钢发生了再结晶;应变速率增加,变形量较大时,变形后静态再结晶明显。变形温度对静态软化行为有显著影响,温度越高,静态软化进行的越迅速。 相似文献
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研究了254SMo、904L和317L超级奥氏体不锈钢在650、700和750℃下30%Na2SO4+30%K2SO4+20%NaCl+20%KCl混合熔盐中的热腐蚀行为。通过腐蚀动力学以及腐蚀产物成分和形貌分析,探究了3种不锈钢在熔融混合盐中的高温腐蚀机理。结果表明,3种不锈钢在不同温度下均表现为失重,耐蚀性顺序为254SMo>904L>317L不锈钢;熔融的氯盐加速腐蚀,主要遵循“电化学腐蚀+氯活性腐蚀”腐蚀机制,硫酸盐通过“碱性助溶”机制溶解和破坏腐蚀层,从而造成严重的内部和晶间腐蚀;在两种腐蚀机制中,以氯腐蚀为主,硫腐蚀为辅;提高Mo和Ni含量可以在一定程度上改善奥氏体不锈钢的耐高温腐蚀性。 相似文献
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利用金相显微镜、SEM、拉伸试验机研究铸态304奥氏体不锈钢在高温下的力学性能和变形组织特征.结果表明,随着温度的升高,304不锈钢的强度在300~950℃迅速下降,950~1250℃下降变缓;延伸率在950℃时达到最大,为86.28%;断面收缩率在950℃时最大,为94.45%.同时对304不锈钢高温拉伸试样断口进行了宏观和微观形貌观察,并探讨了断口形貌的成因及影响材料塑、韧性的因素. 相似文献
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Laser surface hardening of austenitic stainless steel 总被引:2,自引:0,他引:2
S. M. Levcovici D. T. Levcovici V. Munteanu M. M. Paraschiv A. Preda 《Journal of Materials Engineering and Performance》2000,9(5):536-540
For the purpose of studying the possibilities of increasing the wear resistance, keeping a high level of corrosion strength,
austenitic stainless steel specimens mainly containing 19.2%Cr and 9.4%Ni were two-step surface alloyed using added materials
(AMs) with hard particles of carbides (WC), nitrides (TiN), and borides (TiB2). The simultaneous melting of AM and surface layer was performed by a CO2 continuous wave laser on a numerically controlled X-Y table. On these specimens, the microstructural characteristics, microhardness,
and depth of the molten zone were determined, which allowed definition of the AM with the best hardening effect. The research
continued by two-step laser surface alloying of the same base material with different effective AM quantities. The specimens
were processed by continuous wave laser radiation, by multiple-pass with 35% overlap. The alloyed layers were described by
light optical microscopy, x-ray diffractometry, flash spectrometry, and hardness measurement. The conditions to obtain compact
surface layers with 2.5 to 3 times higher hardness than the base material were determined. 相似文献
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《Acta Materialia》2007,55(11):3649-3662
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奥氏体不锈钢表面低温离子硬化处理后,其表面覆盖了一层成分复杂、结合牢固的薄膜,不仅影响了不锈钢表面的外观质量,而且还影响到其表面的耐蚀性能.对奥氏体不锈钢低温离子渗碳的试样进行电化学亮化处理,并对亮化处理前后硬化层的表面形貌、表面粗糙度、组织结构、显微硬度及耐蚀性能做了比较.结果表明,虽然亮化处理后不锈钢表面硬化层的厚度和硬度略有减小,但却能显著提高其表面的耐蚀性能,表面较亮化处理前更加光滑,Ra由0.27μm减小到0.09μm.因此,在奥氏体不锈钢表面低温离子硬化处理后再进行一次表面亮化处理是十分必要的. 相似文献
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B. Karthik R. Veerababu D. V. V. Satyanarayana 《Metals and Materials International》2016,22(3):413-423
Effect of aging and oxidation on strain hardening behaviour of a nickel-free high nitrogen austenitic stainless steel has been investigated using room temperature tensile tests and TEM. The alloy in both oxidised and unoxidised conditions exhibits a transition in flow behaviour that can be described best by the Ludwigson flow relationship as evident from the lowest values of the sum of residual squares, χ 2, of the fit. The transition in macroscopic flow behaviour with strain has been correlated to change in deformation mechanism from planar slip in the low strain regime (LSR) to deformation twinning and slip in the high strain regime (HSR) in solution treated (ST) condition of the alloy. However, the LSR of the alloy aged for longer times (>100 h) is characterized by the formation of dislocation tangles, while the HSR is marked by the formation of well-defined finer dislocation cell structure. This difference in deformation sub-structures in low and high strain regimes between ST and long term aged samples has been correlated to the change in stacking fault energy due to the precipitation of Cr2N and σ-phases. Further, the alloy in ST condition exhibits the highest strain hardening rate, which then progressively decreases with aging time. 相似文献
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借助扫描电镜、电子背散射衍射和透射电镜组织观察,对生物医用奥氏体不锈钢316L的形变组织进行了多尺度深入研究,其工程应变量范围为2%~40%。结果表明,当应变>20%时,316L奥氏体不锈钢中的<001>和<111>取向平行于拉伸方向,即出现了大量的变形孪晶和马氏体。从微米尺度和纳米尺度对孪晶和马氏体相变做详细分析发现,形变首先诱发形成变形孪晶,由于孪晶界减小了位错平均自由程而引起位错塞积,进一步诱发马氏体的转变。随着变形量的增加出现了更多的孪晶和α-马氏体,马氏体相变的过程只有γ→α转变,α马氏体主要分布在孪晶界附近,特别是孪晶交叉的位置。其中,奥氏体基体和α-马氏体之间的取向关系为:[011]γ//[011]α,(420)γ//(123)α。 相似文献
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《Scripta materialia》2002,46(7):507-512
The analysis of tensile work hardening of 316 LN steel revealed three-stage behaviour. The anomalous variation in work hardening rate observed at intermediate temperatures is ascribed to dynamic strain ageing. Increased dynamic recovery at high temperatures resulted in a rapid decrease in work hardening rate. 相似文献
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