摘要
为研究金属微塑性成形特点,对厚度不同及粗细两种晶粒尺寸的黄铜箔试样进行了单向拉伸和微弯曲实验,并采用经典塑性理论和应变梯度理论对弯曲回弹角进行了预测.粗晶粒板料试样单向拉伸实验表明,CuZn37黄铜的硬化曲线存在一种明显的尺寸效应,即板料厚度越小,屈服强度越高.弯曲回弹实验结果也存在另一种明显的尺寸效应现象,即板料厚度越小,回弹角越大.对这两种尺寸效应产生的原因进行了分析,指出应变梯度硬化对微成形工艺过程有重要影响.
Uniaxial tensile tests and microbending experiments of brass foil specimens are performed to investigate size effects of metal foils in microforming process.The specimens are annealed at two different temperatures to obtain fine and coarse grain structure.In the paper,the springback angle in microbending process is predicted based on the classical plasticity theory and strain gradient theory.In uniaxial tensile tests,the increasing of material strength with decreasing foil thickness is observed,which indicates obvious presence of size effects for CuZn37 brass foils,especially for coarse grain specimens.In microbending experiments,obvious size-dependences of springback angle are observed,in which the springback angle of metal foils is increasing with foil thickness decreasing.The reasons for these size effects are discussed and the strain gradient hardening is important to microforming process.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2011年第4期15-19,共5页
Materials Science and Technology
基金
国家自然科学基金项目(508350025097517450821003)
German Federal Ministry of Education and Research BMBF(CHN08-041)
