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一种锻造斗齿用低合金耐磨钢热变形行为 被引量:3
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作者 许午阳 刘华 +1 位作者 曹鋆汇 吴胜超 《锻压技术》 CAS CSCD 北大核心 2017年第2期128-132,138,共6页
为研究一种锻造斗齿用新型低合金耐磨钢高温热变形行为,采用Gleeble-1500D热模拟试验机对其试样进行等温压缩试验,获取在变形温度为1173~1473 K、应变速率为0.01~10 s-1下的真应力-真应变曲线,对高温流动应力特征进行研究,分析了高温热... 为研究一种锻造斗齿用新型低合金耐磨钢高温热变形行为,采用Gleeble-1500D热模拟试验机对其试样进行等温压缩试验,获取在变形温度为1173~1473 K、应变速率为0.01~10 s-1下的真应力-真应变曲线,对高温流动应力特征进行研究,分析了高温热变形行为的物理本质,拟合计算材料本构方程中的参数值,为斗齿锻造成形工艺的数值模拟提供材料性能数据。研究结果表明:热变形温度区间内,当应变速率一定时,该材料的流动应力随着变形温度的升高而减小;当变形温度一定时,该材料的流动应力随着应变速率的增大而增大;本构方程能够比较精确地描述材料在热变形过程中的流动应力,预测值与实验值的平均相对误差为2.29%,最大仅为5.37%。 展开更多
关键词 低合金耐磨钢 本构方程 锻造 挖掘机斗齿 高温热变形行为
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High temperature deformation behavior and optimization of hot compression process parameters in TC11 titanium alloy with coarse lamellar original microstructure 被引量:4
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作者 鲁世强 李鑫 +2 位作者 王克鲁 董显娟 傅铭旺 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第2期353-360,共8页
The high temperature deformation behaviors of α+β type titanium alloy TC11 (Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) with coarse lamellar starting microstructure were investigated based on the hot compression tests in the tem... The high temperature deformation behaviors of α+β type titanium alloy TC11 (Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) with coarse lamellar starting microstructure were investigated based on the hot compression tests in the temperature range of 950-1100 ℃ and the strain rate range of 0.001-10 s-1. The processing maps at different strains were then constructed based on the dynamic materials model, and the hot compression process parameters and deformation mechanism were optimized and analyzed, respectively. The results show that the processing maps exhibit two domains with a high efficiency of power dissipation and a flow instability domain with a less efficiency of power dissipation. The types of domains were characterized by convergence and divergence of the efficiency of power dissipation, respectively. The convergent domain in a+fl phase field is at the temperature of 950-990 ℃ and the strain rate of 0.001-0.01 s^-1, which correspond to a better hot compression process window of α+β phase field. The peak of efficiency of power dissipation in α+β phase field is at 950 ℃ and 0.001 s 1, which correspond to the best hot compression process parameters of α+β phase field. The convergent domain in β phase field is at the temperature of 1020-1080 ℃ and the strain rate of 0.001-0.1 s^-l, which correspond to a better hot compression process window of β phase field. The peak of efficiency of power dissipation in ℃ phase field occurs at 1050 ℃ over the strain rates from 0.001 s^-1 to 0.01 s^-1, which correspond to the best hot compression process parameters of ,8 phase field. The divergence domain occurs at the strain rates above 0.5 s^-1 and in all the tested temperature range, which correspond to flow instability that is manifested as flow localization and indicated by the flow softening phenomenon in stress-- strain curves. The deformation mechanisms of the optimized hot compression process windows in a+β and β phase fields are identified to be spheroidizing and dynamic recrystallizing controlled by self-diffusion mechanism, respectively. The microstructure observation of the deformed specimens in different domains matches very well with the optimized results. 展开更多
关键词 titanium alloy coarse lamellar microstructure high temperature deformation behavior processing map hot compression process parameter optimization
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Hot working characteristics of HEXed PM nickel-based superalloy during hot compression 被引量:6
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作者 Gang TAN Hui-zhong LI +4 位作者 Yan WANG Lei YANG Shi-chang QIAO Zheng-qin HUANG Min-xue LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第10期2709-2723,共15页
To study the hot deformation behavior of a new powder metallurgy nickel-based superalloy,hot compression tests were conducted in the temperature range of 1020−1110℃ with the strain rates of 0.001−1 s^−1.It is found t... To study the hot deformation behavior of a new powder metallurgy nickel-based superalloy,hot compression tests were conducted in the temperature range of 1020−1110℃ with the strain rates of 0.001−1 s^−1.It is found that the flow stress of the superalloy decreases with increasing temperature and decreasing strain rate.An accurate constitutive equation is established using a hyperbolic-sine type expression.Moreover,processing map of the alloy is constructed to optimize its hot forging parameters.Three domains of dynamic recrystallization stability and instability regions are identified from the processing map at a strain of 0.7,respectively.The adiabatic shear band,intergranular crack and a combination of intergranular crack and wedge crack are demonstrated to be responsible for the instabilities.Comprehensively analyzing the processing map and microstructure,the optimal isothermal forging conditions for the superalloy is determined to be t=1075−1105℃ andε&=10^−3−10−2.8 s^−1. 展开更多
关键词 powder metallurgy nickel-based superalloy hot deformation behavior constitutive equation hot processing map dynamic recrystallization
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Influence of Holding Time on Hot Deformation Behavior of Hard-Deformed Superalloy U720Li
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作者 Zang Ximin Zhao Guangdi +2 位作者 Wu Jinjiang Jiang Haoyuan Yao Xiaoyu 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2024年第9期2446-2457,共12页
To improve the hot workability of hard-deformed superalloy U720Li,the effect of holding time before deformation(5 and 10 min)on hot deformation behavior was investigated by hot compression tests.Results show that the ... To improve the hot workability of hard-deformed superalloy U720Li,the effect of holding time before deformation(5 and 10 min)on hot deformation behavior was investigated by hot compression tests.Results show that the flow stress increases with increase in strain rate,while decreases with increase in deformation temperature and holding time.Based on the obtained Arrhenius-type constitutive models,the calculated peak stresses are in good agreement with experimental values,indicating that this model can accurately predict the hot deformation behavior of U720Li alloy,and the deformation activation energies for the holding time of 5 and 10 min were calculated to be 992.006 and 850.996 kJ·mol^(-1),respectively.Moreover,processing maps of U720Li alloy with these two holding durations were constructed.Through observation of deformation microstructures in each domain of the processing maps,the optimal hot working conditions for the holding time of 5 min are determined to be 1090‒1110℃/1‒10 s^(-1) and 1146‒1180℃/1‒10 s^(-1),and the optimal hot working conditions for the holding time of 10 min are 1080‒1090℃/1‒10 s-1 and 1153‒1160℃/1‒10 s^(-1),indicating that the safe processing window can be obviously enlarged by shortening the holding time reasonably.In the absence of cracking,the dynamic recrystallization(DRX)grain size increases gradually with increasing the deformation temperature and holding time,but it first decreases and then increases with the increase in strain rate.When the deformation temperature is below 1100℃,the DRX mechanism is mainly the particle-induced continuous DRX.As the temperature is raised to above 1130℃,the main DRX mechanism changes to discontinuous DRX. 展开更多
关键词 hard-deformed superalloy hot deformation behavior processing map dynamic recrystallization
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