共查询到18条相似文献,搜索用时 140 毫秒
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45钢低温区热变形行为研究 总被引:1,自引:0,他引:1
利用Gleeble-1500热模拟试验机研究了不同变形条件对45钢低温区热变形行为的影响。试验结果表明:峰值应力随变形温度的降低和应变速率的提高而增大;当应变速率ε≥0.01s-1、变形温度t500℃时,发生动态回复;当应变速率ε≤1s-1、变形温度t≥500℃时,发生动态再结晶。在Sellars-Tegart方程的基础上,建立了45钢低温区加工硬化-动态回复、动态再结晶2阶段流变应力模型;根据试验结果计算拟合了模型中各参数。采用建立的流变应力模型成功预测了动态回复、动态再结晶型应力-应变曲线。利用上述模型对45钢中厚板轧后低温工业热矫直的矫直力进行了预测,其结果与实测值吻合良好。 相似文献
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《中国金属通报》2021,(5)
采用了MMS-200热力模拟机以40CrMnMo钢为实验对象进行了热压缩试验,研究了变形温度850℃~1150℃,变形量0.8,应变速率在0.01~10s~(-1)条件下实验钢的热变形行为。通过分析高温下变形参数对流变应力和奥氏体晶粒尺寸的影响,建立40CrMnMo钢的稳态动态再结晶晶粒尺寸模型。结果表明:变形温度为850℃~1150℃,实验钢在应变速率0.01~0.1s~(-1)下发生连续动态再结晶,应变速率1~10s~(-1)下发生动态回复。通过引入Zener-Hollomon(Z)参数表征变形参数对稳态动态再结晶晶粒尺寸的影响,建立了稳态再结晶晶粒尺寸的数学模型,得出提高应变速率或变形温度较低能使Z参数增大,峰值应力升高且动态再结晶晶粒减小。 相似文献
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摘要:利用 Gleeble-3500 热模拟实验机完成了07MnNiMoDR钢热等温平面应变压缩实验,获得了温度 900~1100℃、应变速率 0.01~1s-1、变形率45%等条件的高温流变行为,其中温度和应变速率对流变应力的影响明显。基于对Arrhenius 方程和 Zener Hollomon 参数的解析,获得了热变形激活能Q,确定了峰值应力本构模型;通过分析应力应变与位错的关系,获得了硬化率及Z参数等与应力之间的内在关联性,建立了加工硬化 动态回复过程的流变应力模型;基于动态再结晶理论,采用Avrami模型计算了动态再结晶体积分数,获得Z参数计算方法,建立了动态再结晶过程的流变应力模型。利用所建立的本构模型完成了预测及对比分析,相关系数r为0.99,所建立的本构关系模型精度很高。 相似文献
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采用Gleeble-1500D热模拟试验机研究30%SiCp/Al复合材料在温度为623~773 K、应变速率为0.01~10 s-1下的热变形及动态再结晶行为。结果表明:材料的高温流变应力-应变曲线主要以动态再结晶软化机制为特征,峰值应力随变形温度降低或应变速率升高而增大,材料热激活能为272.831 k J/mol。以试验数据为基础,建立q-s和?q/?s-s曲线,从而进一步获得动态再结晶的临界应变和稳态应变,通过试验数据的回归分析,建立动态再结晶的临界应变模型和稳态应变模型,并在此基础上,获得所需要材料的动态再结晶图。 相似文献
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用热模拟试验机在1150 ̄850℃变形温度、60 ̄0.1s^-1变形速率条件下对10Ti钢做恒温单道次压缩实验。得到变形激活能420KJ/mol,应力指数12和峰值前流变应力数学模型及临界应变、流变应力、峰值应力与Z参数关系。随变形温度升高,应变速率下降,晶粒大小呈上升趋势。得到动态再结晶晶粒大小与Z参数关系。 相似文献
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16Mn钢热变形流变应力模型及晶粒大小 总被引:2,自引:0,他引:2
利用热变模拟试验装置,在850-1150℃变形温度,0.1-60 s^-1变形速率条件下,16Mn钢单道次压缩试验得到热变形的流变应力模型为a=4.4^e0.158 e^7.22×10^-5T exp(4383/T)形变激活能Q为366 kj/mol,应力指数n为9.56。>900℃出现明显的动态再结晶,应力一应变曲线呈单峰状;<850℃出现动态回复。流变应为a、峰值应为ap、再结晶晶粒大小与Z参数呈线性关系a(c=0.2)=3.67Z^0.098;an=2.9Z^0.11;Dr=1.5.13Z^-0.046。 相似文献
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在Gleeble-3500热模拟试验机上对Ti-25Al-14Nb-2Mo-1Fe合金进行了等温恒应变速率压缩试验,研究了在变形温度为950~1 100℃,应变速率为0.001~1 s-1,最大变形程度为50%的条件下合金的热压缩变形流变应力行为与微观组织演变。结果表明:Ti-25Al-14Nb-2Mo-1Fe合金的流变应力对变形温度和应变速率均较为敏感,其流变应力曲线具有应力峰值、流变软化和稳态流变的特征。在变形温度为950℃,应变速率为0.001~0.1 s-1的条件下,Ti-25Al-14Nb-2Mo-1Fe合金的热变形特性为片层组织球化,其热变形机制可用晶界分离球化模型进行解释说明;在变形温度为1 000~1 100℃,应变速率为1 s-1的条件下,材料只发生了动态回复现象;在变形温度为1 050~1 100℃,应变速率为0.001~0.1 s-1的条件下,材料发生了动态再结晶现象。 相似文献
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The hot deformation behavior of S31042 austenitic heat-resistant steel was investigated over the temperature range of 900-1200 ℃ and strain rate range of 001-10 s-1 using hot compression tests and the corresponding flow curves were obtained. The hot deformation activation energy of the test steel is 625 kJ/mol. The hot deformation equation and the relationship between the peak stresses, deformation temperature and strain rate were set up. The Zener-Hollomon parameter under various conditions was determined. The relation between the Zener-Hollomon parameter and the microstructure evolution of test steel was discussed. With the decrease of Zener-Hollomon parameter, the microstructure of test steel transforms from deformation instability to dynamic recovery, partial dynamic recrystallization, full dynamic recrystallization with equiaxial structure, and finally to full dynamic recrystallization with mixed crystal structure. The deformation condition can be adjusted easily by utilizing the Zener-Hollomon parameter to obtain equiaxial microstructure. 相似文献
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The hot compression tests were carried out on a SPHC steel at the temperature range of 900~1150℃ and strain rate range of 0.1~10s-1, which the maximum true strain is 0.8. The activation energy of tested steel was calculated, which was 299.4 KJ /mol. The critical stresses and strains for initiation of dynamic recrystallization were determined based on changes in the work hardening rate ( ) as functions of the flow stress ( ) or strain ( ), respectively. The dependence of the peak strain ( ), the peak stress ( ), and the steady state stress ( ) were determined based on the Zener-Hollomen parameter. The mathematical models of the flow stress evolution were established in the hardening and dynamic recovery region and dynamic recrystallization region, respectively. The average error between experimental and predicted curves was around 3.26%. 相似文献
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The hot compression tests on an SPHC steel were carried out in the temperature range of 900-1150 ℃ and strain rate range of 0.1-10 s-1,in which the maximum true strain is 0.8.The activation energy of test steel was calculated,to be 299.4 kJ/mol.The critical stresses and strains for initiation of dynamic recrystallization were determined based on changes of the work hardening rate(θ)as a function of the flow stress(σ)or strain(ε),respectively.The dependence of the peak strain(εp),the peak stress(σp),and the steady state stress(σs)were determined based on the Zener-Hollomen parameter.The mathematical models of the flow stress evolution were established in the hardening and dynamic recovery region and dynamic recrystallization region,respectively.The average error between experimental curves and predicted ones was around 3.26%. 相似文献
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用Gleeble-3500热力模拟试验机在温度为1 223~1 323 K,应变速率为0.2~10 s-1的条件下对一种非调质连杆用高碳微合金钢进行了热压缩变形试验,测得了其流变曲线,并观察了变形后的组织.试验结果表明,流变应力和峰值应变随变形温度的降低和应变速率的提高而增大.试验用钢在真应变为0.8,温度为1 223~1 323 K,应变速率为0.2~10 s-1的条件下,发生完全动态再结晶.测得试验用钢的热变形激活能为289.9 kJ/mol,并得出了其热变形方程,以及动态再结晶晶粒尺寸与Zener-Hollomon参数之间的关系和动态再结晶状态图. 相似文献
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Hot deformation behavior of GCr15 (ASTM 52100) steel was investigated using single-hit compression tests on Gleeble-1500 simulator at the temperature range of 850-1100 ℃ and strain rate range of 0. 1-10 s-1. The flow stress constitutive equation of GCr15 steel during hot deformation was determined by stress-strain curves analysis on the basis of the hyperbolic sine equation. And the models of dynamic recrystallization fraction and dynamic recrystallization grain size of GCr15 steel were established by the measured curves and microstructure observation in different experimental conditions. The mean activation energy and the time exponent of dynamic recrystallization kinetics equation in the range of experimental conditions were determined to be 356. 2 kJ/mol and 2. 12, respectively. Meanwhile, the flow stress model was also established by the method of allocating flow stress curve with three main stress values, the saturation stress, the steady state stress and the stress when strain is 0. 1. The flow stress curves predicted by the developed models under different deformation conditions are in good agreements with the measured ones. 相似文献
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Fe16Mn0.6C TWIP钢流变应力和临界动态再结晶行为 总被引:1,自引:1,他引:0
利用Thermecmastor-Z热模拟实验机,得到了Fe16Mn0.6C TWIP钢在变形温度850~1150℃,应变速率0.03~30s-1条件下热压缩变形的真应力应变曲线。进而研究了变形温度、应变速率对Fe16Mn0.6C流变应力和临界动态再结晶行为的影响规律。结果表明,850~1150℃范围内Fe16Mn0.6C热变形的峰值应力随温度的升高而降低,随着应变速率的增大而升高;且在应变速率为0.03 s-1和30 s-1出现明显的应力峰值,材料发生了动态再结晶。最后采用线性回归方法计算出Fe16Mn0.6C的高温变形流变应力本构方程,得出热变形激活能为469kJ/mol;并通过应变硬化速率与流变应力曲线求出了该钢种动态再结晶临界条件与Z参数之间的关系。 相似文献
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对均匀化炉冷态7085铝合金进行高温压缩实验,研究该合金在变形温度为350~450℃、变形速率为0.001~0.1 s 1和应变量为0~0.6条件下的流变应力及软化行为。结果表明:流变应力在变形初期随着应变的增加而迅速增大,出现峰值后逐渐软化进入稳态流变;随着变形温度的升高和应变速率的降低,峰值流变应力降低。采用包含Zener-Hollomon参数的Arrhenius双曲正弦关系描述合金的流变行为。分析和建立了应变量与本构方程参数(激活能、应力指数和结构因子)的关系,研究发现本构方程参数随应变量的增加而减少。合金的流变行为差异与动态回复再结晶和第二相粒子相关。 相似文献