Modeling of grain size effect on micro deformation behavior in micro-forming of pure copper

Chan, Wai Lun; Fu, Ming; J, Lu; Liu, Jianguang

doi:10.1016/j.msea.2010.07.009

Cited by 147 publications

(68 citation statements)

References 29 publications

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“…When the microstructure is kept as a constant, only a few grains are involved within the micro scale components through the dimension of interest, and thus there are only a few grains located in the deformation zone. Chan et al [7] proposed that size effects were caused by the orientation, size and position of grains within the specimen and the small size of the workpiece.…”

Section: Introductionmentioning

confidence: 99%

“…This phenomenon has been validated by Echenhualler et al [10] in the upsetting tests at an elevated temperature by using micro specimens of CuZn15 and stainless steel. An alternative approach to reduce the influence of size effects is to refine grain size within the deformed part, which has been investigated by a large number of researchers [7,11,12].…”

Section: Introductionmentioning

confidence: 99%

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Influences of temperature and grain size on the material deformability in microforming process

Jiang

Zhao

et al. 2016

Int J Mater Form

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This paper investigated the influences of temperature and grain size on the deformability of pure copper in micro compression process. Based on the dislocation theory, a constitutive model was proposed taking into account the influences of forming temperature, Hall-Petch relationship and surface layer model. Vacuum heat treatment was employed to obtain various grain sizes of cylindrical workpieces, and then laser heating method was applied to heat workpieces during microforming process. Finite element (FE) simulation was also performed, with simulated values agreed well with the experimental results in terms of metal flow stress. Both the FE simulated and experimental results indicate that forming temperature and grain size have a significant influence on the accuracy of the produced product shape and metal flow behaviour in microforming due to the inhomogeneity within the deformed material. The mechanical behaviour of the material is found to be more sensitive to forming temperature when the workpieces are constituted of fine grains. experimental results indicate that forming temperature and grain size have a significant influence on the accuracy of the produced product shape and metal flow behaviour in microforming due to the inhomogeneity within the deformed material. The mechanical behaviour of the material is found to be more sensitive to forming temperature when the workpieces are constituted of fine grains.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influences of temperature and grain size on the material deformability in microforming process

Jiang

Zhao

et al. 2016

Int J Mater Form

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“…Further research from Raulea et al [8] showed that the yield strength is related to the ratio between the grain size and specimen thickness, which was also demonstrated in a planar blanking and bending process. Chan et al [9] investigated the scatter effect of grain mechanical properties with micro-compression process and proposed a finite element model with consideration of grain size and the scatter effect of flow stress, which provided a basis for understanding and modelling of materials size effect in microforming process. Lu et al [10] enhanced this modeling by implanting Voronoi tessellation algorithm into pre-processor of finite element software.…”

Section: Introductionmentioning

confidence: 99%

Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil

Fang

Jiang

Wang

et al. 2015

Int J Adv Manuf Technol

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X. (2015). Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil. International Journal of Advanced Manufacturing Technology, 79 (9-12), 1905Technology, 79 (9-12), -1914 Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil AbstractSize effects play a significant role in microforming process, and any dimensional change can have a great impact on materials' mechanical properties. In this paper, the size effects on deformation behaviour and fracture of phosphor foil were investigated in the form of grain size effect: the ratio of materials' thickness (T) to average grain size (D) by micro tensile tests. The ratio was designed to be closed to but larger than, less than and equal to 1, respectively. The results show that the amount of plastic deformation decreases with the decrease of the ratio of T/D, which indicates that the grain size plays a significant role and grain deformation modes differ when the ratio changes. It is also found that their fractograph reflects different features in terms of micro-dimples and cleavage planes, further demonstrating that when T/D >1, its materials have a tendency to fracture ductilely, while materials would like to conduct brittle fracture when T/D Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil Abstract: In this paper, the size effects on deformation behaviour and fracture of phosphor foil were investigated in terms of the ratio of materials' thickness (T) to average grain size (D) by micro tensile tests. The results show that the amount of plastic deformation decrease with the decrease of the ratio of T/D, which indicates that the grain size plays a significant role and grain deformation modes differ when the ratio changes. It is also found that their fractograph reflect different features in terms of micro-dimples and cleavage planes, further demonstrating that when T/D>1, its materials have a tendency to fracture ductilely, while materials would like to conduct brittle fracture when T/D<1. So the ratio of T/D which is close to 1 can be regards as the divide of ductile fracture and brittle fracture. For T/D<1, a new constitutive model is proposed based on the classic composite model. The model's results are compared with the experimental ones and the efficiency of the developed models is verified.

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“…Fundamental issues relating to materials, processes, tools and machines have been studied intensively in recent years and are well documented in the literature [4][5][6]. However, the deformation mechanisms at the micro scale may be different from those occurring in conventional metal forming operations due to the so-called size effect in the micro-forming process [7,8], where size effects are caused mainly by the interactive effect of grain and specimen sizes on the flow stress [9][10][11]. Therefore, the grain size appears to be the dominant factor which determines the limiting size of the geometrical features that may be fabricated by micro-forming and this means that very small grain sizes, and especially materials having ultrafine grain sizes, are attractive for use in micro-forming operations [12].…”

Section: Introductionmentioning

confidence: 99%

An evaluation of formability using micro-embossing on an ultrafine-grained magnesium AZ31 alloy processed by high-pressure torsion

Xing

Shan

et al. 2015

MATEC Web of Conferences

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Abstract. An ultrafine-grained (UFG) magnesium AZ31 alloy was achieved with an average grain size of ∼200 nm by high-pressure torsion (HPT) at room temperature (RT) under a pressure of 6.0 GPa through 5 turns. Micro-embossing tests were conducted in a V-groove die having a width of 100 m in the temperature range of 298 to 523 K. The formability of UFG AZ31 alloy was evaluated by measuring the percentage of material flowing into the V-groove. The results show that refinement of grain size can significantly improve the formability by increasing the stain rate sensitivity by comparison with the asdrawn AZ31 alloy. The results demonstrate that the UFG AZ31 alloy exhibits excellent formability for fabricating MEMS components with complicated structures.

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Modeling of grain size effect on micro deformation behavior in micro-forming of pure copper

Cited by 147 publications

References 29 publications

Influences of temperature and grain size on the material deformability in microforming process

Influences of temperature and grain size on the material deformability in microforming process

Grain size effect of thickness/average grain size on mechanical behaviour, fracture mechanism and constitutive model for phosphor bronze foil

An evaluation of formability using micro-embossing on an ultrafine-grained magnesium AZ31 alloy processed by high-pressure torsion

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