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In the present work, the effect of friction stir processing parameters on the mechanical properties of an interstitial free steel was studied. Four rotating speeds (800, 1250, 1600, 2000 rpm) and two traverse speeds (31.5 and 63 mm/min) were employed. On both sides of specimens, a nanograin layer with the thickness and nanograins of 150 μm and 50-100 nm were formed, respectively. For the specimen processed at rotating speed of 1600 rpm and the traverse speed of 31.5 mm/min, the maximum strength was achieved, which was about 80% increase in the strength comparing to that of base material. For constant traverse speed, the increase in the rotation speed from 800 to 1600 rpm led to a decrease in uniform and total elongation of friction stir processed samples. By contrast, when the rotating speed exceeded 1600 rpm, the uniform and total elongation was increased again, while there was a drop in strength. The results of microhardness indicate more than threefold increase in the hardness of the stirred zone comparing to that of base material. 相似文献
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This work aims at studying the influence of lubrication on springback in air bending of interstitial free steel sheets with three different orientations namely 0°, 45°, and 90° for the bending analysis. It is observed that lubrication on both punch and die shows the lowest springback compared to the dry conditions. The white grease is more effective in reducing the springback compared to dry and SAE30 oil. A statistical analysis was done to find out appropriate deviation of springback obtained from the experiments and from the material model. It is further noted that the springback exhibited a second-order polynomial relationship with the bend angle. 相似文献
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The dynamic recrystallization behavior of low-carbon steel containing three different amounts of boron(0.002,0.004,and 0.006 wt%) was systematically investigated under various experimental conditions.Low-carbon steel was exposed to temperatures ranging from 900 to 1100 °C,strain rates from 0.1 to 10 s-1,and inspection of the initial austenite grain size at 1150 °C.The resulting stress–strain curves are observed to possess two classifications of behavior,dynamic recovery and dynamic recrystallization,while the initial austenite grain size increases directly proportional to boron concentration.Additionally,the characteristic points of the flow curves were analyzed by regression method in which the peak and critical stresses decreased in response to an increase in boron composition,indicating that a softening effect appears with the addition of boron.On the contrary,peak and critical strains increased as boron content increased,indicating that boron has the ability to delay the onset of dynamic recrystallization.Lastly,the kinetics model of dynamic recrystallization for three boron-treated steels was established. 相似文献
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N. P. Gurao P. Kumar A. Sarkar H.-G. Brokmeier Satyam Suwas 《Journal of Materials Engineering and Performance》2013,22(4):1004-1009
Bulk texture measurement of multi-axial forged body center cubic interstitial free steel performed in this study using x-ray and neutron diffraction indicated the presence of a strong {101}〈111〉 single texture component. Viscoplastic self-consistent simulations could successfully predict the formation of this texture component by incorporating the complicated strain path followed during this process and assuming the activity of {101}〈111〉 slip system. In addition, a first-order estimate of mechanical properties in terms of highly anisotropic yield locus and Lankford parameter was also obtained from the simulations. 相似文献
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加热速率和形变量对IF钢再结晶温度的影响 总被引:4,自引:2,他引:4
采用膨胀仪法研究了4种退火加热速率对不同冷形变量的IF钢再结晶温度的影响。IF钢的再结晶温度随加热速率的增加而提高,随变形量的增大而降低,如将膨胀曲线的微分最低点定为再结晶温度,在形变量为ε=1.2的条件下,当加热速率由20℃/h提高到400℃/h时,该钢的再结晶温度由645℃提高到664℃。当加热速率保持不变,形变量由0.8增大至1.2时,再结晶温度下降约10℃左右。 相似文献
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研究了钢的再结晶对热浸铝过程金属间化合物(IMCS)层的稳定性影响,结果表明:304不锈钢在热浸镀过程的再结晶结构重排造成该钢材表面形成了非保护性IMCS层,该合金的腐蚀动力学满足线性规律;再结晶程度较轻的410不锈钢表面形成了稳定且致密的Fe2Al5层,该层延缓了其在热浸铝过程的失效。钢材的再结晶对于热浸镀铝过程中界面金属间化合物的影响包括:(1)再结晶可降低IMCS的形核和生长能量,尤其是Fe4Al13相;(2)再结晶引起的晶粒沿密排方向排布可降低Al离子的扩散速率;(3)再结晶加剧了IMCS/钢界面处的应力失配,尤其是奥氏体钢。 相似文献
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研究了强变形量对Q215钢再结晶激活能的影响,结果表明,Q215钢再结晶激活能随其变形量的增加而减小。 相似文献
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游离粒子对摩擦辅助电铸技术的影响 总被引:2,自引:0,他引:2
摩擦辅助电铸技术是采用不添加任何添加剂的标准电铸液,在阴阳极之间添加不导电的游离粒子,在电铸过程中运动的阴极带动游离粒子不断摩擦、挤压电铸层,可得到外观表面平整、光亮、无任何麻点、针眼、结瘤等缺陷的电铸层,其机械性能也非常优异.游离粒子在电铸过程中起到了至关重要的作用.选用不同直径的硅酸锆球,作为新工艺的摩擦介质,通过对比试验方法来研究游离粒子的直径对电铸层表面形貌、微观组织和机械性能的影响规律.试验结果表明,在摩擦辅助电铸过程中,游离粒子的直径对电铸层外表面质量影响非常明显.粒子直径过小,电铸工艺处于亚复合电铸状态,易造成电铸层起皮;直径太大,易导致电铸层摩擦不均匀;当粒子直径在0.4~2.0 mm之间时,能获得表面光亮、平整和强度较高的电铸层. 相似文献
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外加纳米SiC颗粒对Q235钢组织与硬度的影响 总被引:2,自引:0,他引:2
在实验室条件下通过对纳米颗粒进行预分散的方法,研究了向熔体中外加SiC纳米粉的可行性以及对Q235钢组织与性能的影响.结果表明,采用将超细颗粒预分散的方法可以将纳米SiC颗粒加入高温熔体中;外加纳米SiC颗粒在Q235钢熔体中可成为形核核心,对铸态组织起到明显细化作用;加入5%的纳米陶瓷颗粒和未加入纳米陶瓷颗粒的Q235铸态晶粒组织相比,晶粒组织大幅度细化;与原Q235钢的硬度相比,经纳米SiC粉体强化后的Q235钢的硬度明显增加,当纳米SiC的加入量为5%时,显微硬度的提高幅度高达147%. 相似文献
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渗碳体粒子尺寸对低碳钢铁素体动态再结晶的影响 总被引:1,自引:0,他引:1
利用单向热压缩实验和OM、SEM、EBSD及TEM技术,研究了低碳钢铁素体晶粒尺寸相似、渗碳体粒子尺寸不同的两种原始组织在700℃、0.01 s-1条件下的组织演变过程,分析了渗碳体粒子尺寸对铁素体动态再结晶的影响.实验结果表明:变形过程中,在尺寸较大的渗碳体粒子附近容易产生大的应变梯度,通过粒子激发形核导致动态再结晶核心的形成.在变形初期,动态再结晶核心主要在尺寸大于1.0 μm的渗碳体粒子附近形成;随着应变量的增加,动态再结晶核心也可以在0.5-1.0 μm的渗碳体粒子附近形成;而小于0.3 μm的渗碳体粒子附近无法形成大的应变梯度,只能钉扎位错和亚晶界,阻碍动态回复和动态再结晶的发展. 相似文献
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利用热模拟试验机对Q235钢进行双道次压缩试验,通过研究其在静态变形过程中再结晶分数的变化规律,揭示不同因素对其静态再结晶的影响机制。结果表明,变形量增加,温度升高,原始奥氏体晶粒尺寸减小及应变速率提高,可加速Q235钢的静态再结晶过程。同时,通过降低变形温度和增加变形量可细化Q235钢奥氏体晶粒。 相似文献
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A. K. Lakshminarayanan V. Balasubramanian 《Journal of Materials Engineering and Performance》2011,20(1):82-89
Welded regions of interstitial free (IF) steel grades in the vicinity of weld center exhibits larger grains because of the prevailing thermal conditions during weld metal solidification. This often causes inferior weld mechanical properties. In the present study, tensile properties, charpy impact toughness, microhardness, microstructure, lowest hardness distribution profile, and fracture surface morphology of the gas tungsten arc welded (GTAW) and friction stir welded joints were evaluated, and the results are compared. From this investigation, it is found that friction stir welded joint of IF steel showed superior tensile and impact properties compared with GTAW joint, and this is mainly due to the formation of very fine, equiaxed microstructure in the weld zone. 相似文献
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