Papers by Keyword: Processing Map

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Authors: Qing Hua Yuan, Kun Lei, Zong Ke Shao, Zhong Guo Huang, Yu Zhou
Abstract: High temperature tensile properties of Ti-4Al-6V material were obtained through high temperature tensile test, and processing maps of the material were drawn by Matlab, then strain rate sensitivity exponent m was calculated. The value of m obtained through constant strain rate stretching method was compared to the former. The results showed that processing map could not only predict the good workability region and flow instability region but also calculate the value of m accurately.
Authors: Yan Hui Yang, Dong Liu, Guo Jie Gao, Jian Guo Wang
Abstract: Isothermal compression tests were conducted at various temperature and strain rate combinations over the hot working range (880 to 1040°C and 0.01 to 10.0 s-1) of TC11 alloy. Based on the experimental data, the strain rate sensitivity factors m were calculated. Both the efficiency of power dissipation and the instability parameter were computed, and then processing maps incorporated instability maps were accordingly established at strains of 0.1, 0.3 and 0.6. A method to optimize the forging process of Titanium alloy blisk was proposed based on the processing map. The optimized process of TC11 alloy blisk was achieved using the proposed method and was verified by numerical simulation and experiment. The results showed that this optimal process is applicable to produce blisk with duplex structures.
Authors: Yong Xue, Zhi Min Zhang, Yao Jin Wu
Abstract: Quantities AZ80 magnesium alloy billets were compressed with 60% height reduction on hot process simulator at 200,250,300,350,400,450°C under strain rates of 0.001, 0.01, 0.1,1 and 10s-1.The processing maps based on the Dynamic Material Modeling (DMM) were constructed, which is useful to analyze the deformation mechanism and the destabilization mechanism of AZ80 alloy. If the mechanical property of AZ80 alloy is taken into consideration, the optimal deformation processing parameters from the processing maps are the deformation temperatures ranging from 300 to 350°C and strain rates ranging from 0.001 to 0.01s-1. Meanwhile, a flow stress model with eight parameters is used to characterize the dynamic recrystallization strain softening of AZ80 alloy.
Authors: S. Ramanathan, R. Karthikeyan, B.C. Pai
Authors: Guang Lu, Zhi Min Zhang, Yong Xue, Bao Cheng Li
Abstract: Quantities Mg-12Gd-5Y-3Zn-0.6Zr magnesium alloy billets were compressed with true strain 0.7 on hot process simulator at 350,400,450,480°C under strain rates of 0.001, 0.01, 0.1 and 0.5s-1. A constitutive model with a few parameters is used to characterize the dynamic recrystallization strain softening of Mg-12Gd-5Y-3Zn-0.6Zr alloy, which comprehensively reflect the effects of the deformation temperature, strain and strain rate on flow stress.
Authors: K.P. Rao, Y.V.R.K. Prasad, K. Suresh
Abstract: Forging of a rib-web shape in rolled AZ31B magnesium alloy was conducted in the transverse direction at speeds of 0.01-10 mm s-1 in the temperature range 300-500 °C with the objective of validating the flow anisotropy. The finite element programme DEFORM was used to simulate the forging process to obtain the local values of strain and strain rate. Forgings done along the transverse direction at temperatures higher than 400 °C resulted in a symmetrical cup-shape while those done at lower temperatures exhibited an elliptical boat-shape with the major axis coinciding with the rolling direction and the minor axis aligning with the normal direction. This anisotropy of flow was due to the strong basal texture in the rolled plate and the dominance of prismatic slip at lower temperatures. At higher temperatures, pyramidal slip dominates along with cross- slip as the recovery mechanism, which reinstates the symmetry of flow by destroying the initial texture.
Authors: Li Wei Zhu, Xin Nan Wang, Yue Fei, Jing Li, Zhi Shou Zhu
Abstract: The hot deformation behavior of Ti-4.5Al-3V-2Mo-2Fe (SP-700) titanium alloy in the temperature range of 650°C~950°C and constant strain rate of 0.01, 0.1, 1 and 10s-1 has been investigated by hot compressive testing on the Gleeble-1500D thermal simulation test machine. The experimental results indicated that the hot deformation behavior of SP-700 alloy was sensitive to the deformation temperature and strain rate. The peak flow stress decreased with the increase of temperature and the decrease of strain rate. The flow curves characteristic under different deformation parameters show significant different. Analysis of the flow stress dependence on strain rate and temperature gives a stress exponent of n as 4.8235 and a deformation activation energy of Q as 410kJ/mol. Based on the dynamic materials model, the processing map is generated, which shows that the most peak efficiency domain appears at the temperature of 725°C~775°C and the strain rate of 0.001 s-1~0.003s-1 with a peak efficiency of 45% at about 750°C/0.01s-1.
Authors: Jian Guo Wang, Dong Liu, Tao Wang, Yan Hui Yang
Abstract: The deformation behavior of a Udimet720Li superalloy under hot compression tests was characterized in the temperature range of 1060~1160°C and strain rate range of 0.001~20s-1. Processing maps were conducted at a series of strains to calculate the efficiency of hot working and to recognize the instability regions of the flow behavior. A Zener-Hollomon parameter is given to characterize the dependence of peak stress on temperature and strain rate. The efficiency of power dissipation of the Udimet720Li superalloy obtained in a strain range of 0.1~0.7 are essentially similar, which indicates that strain does not have a significant influence and the instability region shown in high strain and high strain rates at all temperatures. The regions for the full recrystallization can be divided by the dissolution beginning temperature of primary γ'which are the optimum hot working parameters.
Authors: Guo Qing Lin
Abstract: The hot deformation behavior of Zr-4 alloy was studied in the temperature range 650-900°C and strain rate range 0.005-50s-1 using processing maps. The processing maps revealed three domains: the first occurs in the temperature range 780-820°C and strain rate range 0.005-0.05s-1, and has a peak efficiency of 45% at 790°C and 0.005s-1; the mechanism is the dynamic recrystallization. The second occurs in the temperature range greater than 900°C and strain rate range 0.05-0.8s-1, and has a peak efficiency of 40% at 900°C and 0.5s-1, which are the domains of dynamic recovery. In addition, the instability zones of flow behavior can also be recognized by the maps in the temperature range 650-780°C and strain rate range 0.01-0.1s-1, which should be strictly avoided in the processing of the material. Zr-4 alloy is the material for pressure tube applications in nuclear reactors and has better strength and a lower rate of hydrogen uptake compared to other materials under similar service conditions.
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