共查询到20条相似文献,搜索用时 46 毫秒
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采用Gleeble-3500热/力动态模拟试验机研究了AZ91镁合金在变形温度为250~400℃、应变速率为10-3~1 s-1条件下的热压缩变形行为。并在此基础上,采用Gleeble-3500模拟累积叠轧焊轧制方法,对其在累积叠轧焊(ARB)过程中的组织演变和晶粒细化的机制进行了研究。结果表明:AZ91镁合金在热压缩变形过程中,适宜的变形工艺为变形温度350~400℃、应变速率10-3~10-2 s-1。AZ91镁合金在变形温度350℃、应变速率0.01 s-1和变形量80%为工艺条件的累积叠轧焊过程中,晶粒在第一次轧制过程中明显细化,其机制发生了动态再结晶,在随后的叠轧过程中,晶粒细化程度有限,但组织均匀程度增加。 相似文献
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35CrMo钢动态再结晶过程数值模拟与试验研究 总被引:8,自引:0,他引:8
以热物理模拟试验研究为基础,得出35CrMo钢发生动态再结晶时的数学模型。采用热一力耦合的弹塑性有限元法对35CrMo结构钢在热变形过程进行了数值模拟。变形的不均匀性导致动态再结晶进行的不等时性,动态再结晶的发生初始于大变形区,随着应变的增加,逐渐向粘着区和自由变形区延伸。同时预测热变形过程的形变量、形变速率和形变温度对再结晶微观组织演变的影响。在一定温度下,再结晶晶粒尺寸的大小与应变速率呈反方向变化,随着变形的进行,试样内的晶粒尺寸趋于细化和均匀化。在一定应变速率下,随着形变温度的降低,再结晶晶粒尺寸趋于细化,导致了锻件的综合性能提高。为了观察显微组织演化过程,对模拟结果进行了金相法验证,模拟结果与实验结果比较吻合,模拟的结果是合理的。 相似文献
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厚规格E36高强度船板轧制工艺研究 总被引:1,自引:0,他引:1
为保证厚规格(>50mm)E36高强钢板的强度和冲击韧性合格率在95%以上,研究了不同轧制工艺对其性能的影响.结果显示,较低的加热温度(1200~1240℃)、较低的终冷温度(600~650℃)可使产品满足力学性能标准要求. 相似文献
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通过一种铌微合金钢高温下(900~1100℃)不同应变速率(0.01~10s<'-1>)的热模拟单道次压缩试验,结合组织观察,研究了热变形参数对动态再结晶过程的影响,求出动态再结晶形变激活能及相关参数,建立了该钢的热变形本构方程.实验结果表明,合金元素的添加,由于固溶原子拖曳及析出物的钉扎作用,增加了动态再结晶激活能,显著抑制了该钢的动态再结晶及晶粒长大过程.原始奥氏体晶粒尺寸增大、变形温度降低及应变速率增大将抑制动态再结晶过程. 相似文献
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《金属学报(英文版)》2017,(9)
The dynamic recrystallization behavior of 25 CrMo4 steel was systematically investigated by compression deformation at different temperatures and strain rates on a Gleeble 1500 thermal mechanical simulation tester. The flow curves under different deformation conditions were obtained, and the effects of deformation temperature and strain rate on the appearance of the flow curves were discussed. Based on the experimental flow curves, the activation energy determined by regression analysis was Q = 337 k J/mol, and the constitutive model was constructed. All the characteristic points of the flow curves were identified from the work hardening rate curves(θ=dó/dεvs ó), which were derived from the flow curves. Then, the kinetics model of dynamic recrystallization was determined by combining the Avrami equation with the stress loss resulted from the dynamic recrystallization. With the aid of the kinetics model, the effect of strain on the efficiency of power dissipation was discussed. Furthermore, the optimum parameters for the forging process were determined based on the processing maps. 相似文献
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5083铝合金热轧板研究 总被引:6,自引:1,他引:6
针对5083铝合金铸锭热轧时出现的开裂缺陷,研究了钠脆机理,分析了钠的来源,给出了解决办法;应用正交设计实验,解决了规定非比例伸长应力不稳定难题;研究了腐蚀机理,提出了提高抗蚀性能的手段。 相似文献
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Zhengbing Xiao Yuanchun Huang Yu Liu 《Journal of Materials Engineering and Performance》2018,27(3):924-932
To better understand the dynamic recrystallization (DRX) behavior of 35CrMo steel during hot deformation, a series of isothermal compression tests were carried out at different temperatures and strain rates. Using a constitutive equation built from the data obtained and the Arrhenius equation, the activation energy for hot deformation was determined through regression to be 342.69 kJ/mol. A model of the DRX kinetics was also constructed to characterize the influence of accumulated strain, temperature and strain rate on DRX evolution, which revealed that lower temperatures and higher strain rates require greater strain to achieve the same DRX volume fraction. Optical examination of the microstructure after deformation confirmed that this model accurately reflects reality and that grain size varies directly with deformation temperature, but inversely with strain rate. 相似文献
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归纳了现有典型的多个C-Mn钢奥氏体再结晶过程的物理冶金模型,并采用2组模拟热连轧变形参数,对各模型进行了评价.对于再结晶模型,针对所设定的变形条件,得出可用于计算再结晶的模型有J.J.Jonas & Hodgson模型、Sellars模型、Yada模型和Saito模型.对可用于计算再结晶的模型在变形过程中每道次的再结晶情况及晶粒尺寸的变化情况进行了详细分析,得出J.J.Jonas&Hodgson的模型适用性较好.对于流变应力的模型,在相同变形条件下,Misaka模型和J.J.Jonas & Hodgson模型的结果较接近,而志田茂模型的结果与以上两个模型相差较大.因为缺少工业现场的数据作比较,对模型的工业适用性尚不能确定. 相似文献