基于应变梯度塑性理论的微塑性成形力学性能

摘要/Abstract

摘要：

不同厚度的T2紫铜试样的单向拉伸、微硬度和微弯曲试验表明，材料的力学行为与内禀的材料特征参数相关：厚度为30μm的板材，其拉伸强度比厚度为150μm的板材提高了28%，平均晶粒尺寸D为50μm的细晶，其拉伸强度比平均晶粒尺寸D为120μm的粗晶拉伸强度提高了33%，拉伸时呈现出“越小越强”的特征；当压痕深度与板材厚度的比值大于0.2时，压入深度越大，压痕硬度越大，呈现出“越大越硬”的现象；回弹角随板料厚度的减小而增大，当材料厚度小于一定值（0.06mm）时，材料的应变梯度硬化效应使得回弹角随板料厚度的变化更为剧烈，这种变化与采用应变梯度塑性理论预测的结果基本一致。

关键词: T2紫铜, 力学性能, 应变梯度理论, 微塑性成形

Abstract:

The unilateral stretching, microhardness, and microbending tests of T2 copper samples with different thicknesses show that the mechanical behavior of material is relevant to the intrinsic characteristics of material: the tensile strength of sheet material with thickness of 30μm is increased by 28% compared with that of the sheet material with thickness of 150μm, the tensile strength of the fine grain with average grain size D of 50μm is improved by 33% compared with that of the coarse grain with average grain size D of 120μm, with the “the finer, the stronger” characteristic displayed. When the ratio of the indentation depth to the sheet thickness is more than 0.2, the deeper the indentation is, the harder the indentation is, with the “the deeper, the harder” characteristic displayed. The springback angle decreases as the thickness of the sheet increases. When the thickness of sheet is less than a certain value (0.06mm), the strain gradient hardening effect of the material makes the change of springback angle with the change of sheet thickness stronger. This change is substantially consistent with the results predicted by using the strain gradient plastic theory.

Key words: T2 red copper, mechanical property, strain gradient theory, micro plastic forming

中图分类号:

TG301

郭幼丹, 程晓农. 基于应变梯度塑性理论的微塑性成形力学性能[J]. 中国机械工程, 2015, 26(5): 689-693.

Guo Youdan, Cheng Xiaonong. Mechanical Properties of Micro Plastic Forming Based on Strain Gradient Theory[J]. China Mechanical Engineering, 2015, 26(5): 689-693.

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http://www.cmemo.org.cn/CN/Y2015/V26/I5/689

参考文献

[1]Geiger M,Mebner A,Engel U.Production of Microparts-size Effects in Bulk Metal Forming.Similarity Theory[J]. Production Engineering,1997,4(1):55-58
[2]Koeanda A,Pres T.The Effeet of Miniatunzation on the Final Geometry of the Bent Produet[C]//the English Iniemational Conference on Metal Forming.Rotterdam,2000:68-72.
[3]Hutehinson J W.Plastieity at the Micro-sceale.Intemational[J].Joumal of Solids and Structures,2000,37(1/2):225-238.
[4]Cosserat E,Cosserat F.Theorie Des Corps Deformables[J]. Hermann & Fils, 1909(3):26-29.
[5]Mindlin R D.Second Gradient Plasticity[J].Adv. App. Mech.,1997,33:295-361.
[6]Fleck N A,Muller G M,Ashby M F,et al. Strain Gradient Plasticity:Theory and Experiment[J]. Acta Metall. Mater.,1994,42:475-487.
[7]Stolken J S,Evans A G.A Microbend Test Method for Measuring the Plasticity Length Scale[J]. Aeta Metall. Mater.,1998,46:5109-5115.
[8]Aifantis E C.On the Microstructural Origin of Certain Inelastic Models[J].Mater.Engng.Technol.,1984,106:326-330.
[9]Aifantis E C.Strain Gradient Interpretation of Size Effects[J].International Journal of Fracture,1999,95(1/4):299-314.
[10]Lam D C C,Yang F,Chong A C M,et al.Experiments and Theory in Strain Gradient Elasticity[J].Mech. Phys. Solids,2003,51:1477-1508.
[11]黄克智，邱信明，姜汉卿.应变梯度理论的新进展(一)偶应力理论和SG理论[J].机械强度，1999，21(2)：81-87.
Huang Kezhi,Qiu Xinming,Jiang Hanqing. Recent Advances in Strain Gradient Plasticity-Ⅰ——Couple Stress Theory and SG Theory[J]. Journal of Mechanical Strangth,1999,21(2):81-87.
[12]李河宗，董湘怀，王倩,等. CuZn37黄铜板料微塑性成形中的尺寸效应研究[J].材料科学与工艺，2011，19（4）：15-19.
Li Hezong,Dong Xianghuai,Wang Qian. Size Effects of CuZn37 Brass Foil in Microforming[J]. Materials Science and Technology, 2011, 19(4):15-19.
[13]聂志峰,周慎杰,韩汝军,等.应变梯度弹性理论下微构件尺寸效应的数值研究[J].工程力学，2012，29（6）：38-46.
Nie Zhifeng,Zhou Shenjie,Han Rujun,et al. Numerical Study on Effects of the Microstructures Based on Strain Gradient Elasticity[J]. Engineering Mechanics,2012,29(6):38-46.
[14]周丽，李守新，黄树涛.运用应变梯度塑性理论模拟颗粒增强铝合金强度及延伸率的尺寸效应[J].功能材料，2008，39（12）：2101-2105.
Zhou Li,Li Shouxin, Huang Shutao. Simulation of Size Effect on Strength and Elongation of Al Alloy Wity Rarticles Reinforcement Using Strain Gradient Plasticity Concept[J].Journal of Functional Materials,2008,12(39):2101-2105.
[15]Fleck N A, Hutchinson J W. A Phenomenological Theory for Strain Gradient Affects in Plasticity[J]. Journal of the Mechanics and Physics of Solids, 1993, 41: 1825-1857.
[16]Fleck N A, Hutchinson J W. Strain Gradient Plasticity[J]. Advanced Applied Mechanics, 1997, 33: 295-361.
[17]Saha R, Xue Z, Huang Y, et al. Indentation of a Soft Metal Film on a Hard Substrate: Straingradient Hardening Effects[J].Mech. Phys. Solids, 2001, 49:1997-2014.
[18]Liu Z L, Zhuang Z, Liu X M, et al. A Dislocation-dynamics Based Higher-order Crystalplasticity Model and Applications on Confined Thin-film Plasticity[J]. Int. J. Plast., 2011,27:201-216.