H62黄铜自由微弯曲装置及其尺度效应

Investigation on the Free Micro-bending Device and Size Effect for H62 Brass

微型化和尺度效应使得微弯曲在成形工艺、方法和装置上和传统弯曲有很大差异。本文针对微弯曲成形的特点研制出微弯曲成形装置,主要包括传动机构、模具、数据采集模块和定位系统。利用该装置,在0.077 mm/s的成形速度下,分别对0.1 mm、0.2 mm和0.4 mm厚的H62黄铜超薄板进行自由弯曲实验,根据采集数据得到弯矩-挠度拟合曲线,分析了微弯曲过程中的尺寸效应:即试样尺寸与晶粒尺寸对弯矩的影响规律,结果表明弯矩随着晶粒尺寸的增大而减小,并用表面层模型和细晶强化理论来进行解释。

Since the micro-bending know-how is different from traditional bending,the device for micro-bending is designed according to the characteristics of micro-bending,and the device mainly includes transmission mechanism,die,data acquisition system and positioning system.Using this device,an experiment of free micro-bending was implemented for the ultra-thin sheet of H62 brass with different thicknesses： 0.1mm 0.2mm and 0.4mm,and the velocity of the die is 0.077mm/s.According to the curve of bending moment-defelection which is fitted by the collected data,the results show that bending moment decreases with the increasing of average grain size owing to the size effect influence.This can be explained by the Hall-Petch theory and surface layer modeling.