Metal Workability Analysis in Hot Deformation by Combination Three-dimensional Processing Maps

Including Strain with Finite Element Simulation

LIU Juan  CUI Zhenshan  LI Congxin

(National Die & Mold CAD Engineering Research Center, Shanghai Jiaotong University, Shanghai 200030)

Abstract: The workability consists of two independent parts: state-of-stress (SOS) workability and intrinsic workability. The traditional processing maps proposed by PRASAD on the base of dynamic material model (DMM) only indicate the intrinsic workability dependent on the material properties. A new three-dimensional processing map including strain is built, which describes the variations of power dissipation coefficient and flow instability domains with strain rate, temperature and strain. For metals with typical strain softening such as magnesium alloy, this new three-dimensional processing map has solved the sensitivity of the elevated workability to strain. By combination of the processing map with finite element simulation, the distribution and variation of stress, strain, strain rate, temperature and flow instability domains are obtained under certain thermal deformation conditions. This method can be considered as an effective way to analyze the workability of metals in the whole processes of hot deformation.

Key words: Processing map  Dynamic material model  Power dissipation efficiency  Flow instability  Finite element simulation

CLC No: TG113.26

国家重点基础研究发展计划(973计划, 2006CB705401)资助项目. Received 20070617, received in revised form 20071224

References

[1] RAJ R. Development of a processing map for use in warm-forming and hot forming processes[J]. Metalurgy Transaction A, 1989(12A): 1 089-1 097.
[2] PRASAD Y V R K, SASIDHARA S. Hot working guide: a compendium of processing maps[M]. ASM International, Metal Park, OH, 1997.
[3] JU Quan, LI Dianguo, LIU Guoquan. The processing map of hot plastic deformation of A 15Cr-25Ni-Fe based superalloy[J]. ACTA Metallurgica SINICA, 2006, 42(2): 218-224.
[4] WANG Lingyun, FAN Yongge, HUANG Guangjie, et al. Plastic deformation at elevated temperature and processing maps of magnesium alloy[J]. The Chinese Journal of Nonferrous Metals, 2004, 14 (7): 1 068-1 072.
[5] BAO Ruqiang, HUANG Xu, CAO Chunxiao, et al. Application of processing maps in hot working of titanium alloy[J]. Materials Review, 2004, 18(7): 26-29.
[6] PRASAD Y V R K, SESHACHARYULU T. Processing maps for hot working of titanium alloys[J]. Materials Science and Engineering A, 1998(243): 82-88.
[7] SIVAKESAVAM O, PRASAD Y V R K. Hot deformation behaviour of as-cast Mg–2Zn–1Mn alloy in compression a study with processing map[J]. Materials Science and Engineering A, 2003(362): 118-124.
[8] PRASAD Y V R K. Processing maps: a status report[J]. Journal of Engineering and Performance, 2003(12): 638-645.
[9] ZIEGLER Hans. An introduction to thermomechanics[M]. North-Holland Publishing Company, New York Oxford, 1983.
[10] YIN D L, ZHANG K F, WANG G F, et al. Superplasticity and cavitation in AZ31 Mg alloy at elevated temperatures[J]. Materials Letters, 2005(59): 1 714-1 718.
[11] TAN J C, TAN M J. Superplasticity and grain boundary sliding characteristics in two stage deformation of Mg-3Al-1Zn alloy sheet[J]. Materials Science and Engineering A, 2003(339): 81-89.
[12] AVEDESIAN M M, BAKER Hugh. ASM specialty handbook magnesium and magnesium alloys[M]. ASM International, Metal Park, 1999.