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Journal of Magnesium and Alloys 2022年第9期10卷 2516-2533页

作者： Man Soo Joun Mohd Kaswandee Razali Jae Dong Yoo Min Cheol Kim Jeong Muk Choi ReCAFT Gyeongsang National UniversityGraduate School of Mechanical and Aerospace EngineeringJinju 52828South Korea Gyeongsang National University Graduate School of Mechanical and Aerospace EngineeringJinju 52828South Korea MFRC Research CenterJinju 52818South Korea Jinhap Daejeon 34302South Korea

Here,we developed novel extended piecewise bilinear power law(C-m)models to describe flow stresses under broad ranges of strain,strain rate,and temperature for mechanical and metallurgical calculations during metal forming at elevated *** traditional C-m model is improved upon by formulating the material parameters C and m,defined at sample strains and temperatures as functions of the strain *** coefficients are described as a linear combination of the basis functions defined in piecewise patches of the sample strain and temperature domain.A comparison with traditional closed-form function flow models revealed that our approach using the extended piecewise bilinear C-m model is superior in terms of accuracy,ease of use,and adaptability;additionally,the extended C-m model was applicable to numerical analysis of mechanical,metallurgical,and microstructural ***,metallurgy-related values can be calculated directly from the flow stress *** the proposed model was developed for materials at elevated temperatures,it can be applied over a broad temperature range.

关键词： Flow stress Power law model Piecewise bilinear function Numerical analysis Microstructural prediction peak strain

Effect of Niobium and Titanium on Dynamic Recrystallization Behavior of Low Carbon Steels

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Journal of Iron and Steel Research International 2008年第3期15卷 31-36页

作者： MA Li-qiang LIU Zhen-yu JIAO Si-hai YUAN Xiang-qian WU Di Shenyang Metrology Testing Institution Shenyang 110179 Liaoning China State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China Institute of Research and Development Baosteel Co Shanghai 201900 China

Using a Gleeble 3800 thermo-mechanical simulator, the effect of niobium and titanium on the dynamic recrystallization （DRX） behavior of low carbon steels was investigated. Isothermal single compression tests were performed in the temperature range of 850 to 1 150 ℃ at constant strain rates of 0.1 to 5 s-1. The experimental results showed that the addition of niobium and titanium to the low carbon steels significantly increased both the peak stress and steady state stress. The activation energy of deformation Qd was larger than the activation energy associated with the steady state stress Qss. Furthermore, the difference between Qd and Qss became significant because of the addition of niobium and titanium. DRX is effectively retarded because of solute dragging and dynamic precipitate pinning of niobium and titanium, resulting in higher values of the peak strain and steady state strain. Finally, the influence of niobium and titanium on the DRX kinetics and steady state grain size was determined.

关键词： peak strain activation energy dynamic recrystallization

Hot deformation behavior of AZ91 magnesium alloy in temperature ranging from 350℃ to 425℃

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Transactions of Nonferrous Metals Society of China 2012年第9期22卷 2066-2071页

作者： G. R. EBRAHIMI A. R. MALDAR H. MONAJATI M. HAGHSHENAS Department of Materials Engineering Faculty of Engineering Ferdowsi University of Mashhad Department of Materials Engineering Sabzevar Tarbiat Moallem University Department of Materials Engineering Islamic Azad University Department of Mechanical and Materials Engineering Western University

The flow behavior and microstructure evolution of AZ91 magnesium alloy during a thermomechanical process, hot compression test, was investigated. The specimens were hot compressed at a temperature ranging from 350 ℃ to 425 ℃ and at strain rate of 0.1 s-1 to the strains of 0.3, 0.5 and peak. Microstructural evolutions were studied using optical and scanning electron microscopes. The results show that during the compression process, the recrystallized grains nucleate along the pre-existing grain boundaries. The amount of dynamically recrystallized grains is increased with strain in a sigmoid scheme followed by Avrami equation. The size of dynamically recrystallized grains also increases at the beginning and decreases after reaching the maximum value.

关键词： AZ91 alloy hot compression microstructure evolution recrystallization peak strain

DYNAMIC MECHANICAL BEHAVIOURS OF HIGH Mo AUSTENITIC STAINLESS STEEL DURING HOT DEFORMATION

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Acta Metallurgica Sinica(English Letters) 1992年第7期5卷 60-64页

作者： XU Yourong GU Qing WANG Deying, Shanghai University of Science and Technology, Shanghai, ChinaGU Jufang Q U Tiancai, Shanghai Iron and Steel Research Institute, Shanghai, China XU Yourong, Professor, Department of Materials Science, Shanghai University of Science and Technology, Shanghai 201800, China

The dynamic mechanical behaviours of super low carbon high Mo austenitic stainless steel (00Cr20Nil8Mo6CuN)during hot deformation have been studied by using Formaster-Press hot working simulator. The hot deformation equation, as well as the relationship between peak strain, peak stress and Zener-Hollman parameter, together with the deformation activation energy have been resulted through the experiments.

关键词： hot deformation austenitic stainless steel peak strain peak stress dynamic behaviour