导　　师： 崔令江

学科专业： 080503

授予学位： 硕士

作　　者： ;

机构地区： 哈尔滨工业大学

摘　　要： 随着产品不断的微型化，人们对生产机械微产品的成形工艺有很大的需求。微气压胀形是一种适合生产非常小的金属产品的成形技术，尤其是批量生产。近年来微气压胀形在微成形领域已经成为了一个热点。本文通过一系列试验研究了AZ31B镁合金箔材微气压胀形的变形规律。 通过对0.1mm厚的AZ31B镁合金箔材在245℃进行热处理，得到晶粒大小不同的箔材；通过回归建立了晶粒长大模型；通过对不同厚度的箔材在同一温度、保温不同时间的情况下进行热处理，得到晶粒大小相同的箔材，晶粒大小约为2μm。 利用半球自由胀形试验研究了胀形气压、胀形温度、晶粒大小、箔材厚度、凹模直径对微胀形性能即胀形高度的影响。研究结果为：380℃为最佳微气压胀形温度；在试验气压范围内，随着气压的升高，半球件高度增加，380℃、4.2MPa时胀形高度最大，在15min的胀形时间内达到了682μm，高径比达到0.718；利用热处理后的箔材研究晶粒大小对微气压胀形高度的影响，晶粒越小，微胀形性越好；在晶粒大小相同的情况下，箔材厚度越小，胀形高度越高；半球件完好未发生破裂时，微半球件的高径比随着凹模直径的增加而增大。 在以上研究的基础上，使用组合凹模成形了微筒形件，通过可调节的底销来改变凹模内腔的深度，可以成功胀形出外形与凹模型腔非常相近的筒形件，在380℃、4.2MPa下胀形出高度为510μm的筒形件，入口圆角半径为150μm，直壁与底部平面之间的圆角约为100μm。 利用光学显微镜和扫描电镜研究了AZ31B镁合金箔材微胀形件的组织演变规律以及断裂机制。试验结果表明：随着变形量的增大，晶粒变小，在微胀形过程中发生了动态再结晶；变形越大，再结晶越彻底，晶粒越均匀细小。但微胀形不同部位间晶粒大小相差� With the ongoing miniaturization in products, there is a growing demand for thedevelopment of accurate forming process for mechanical micro-parts. Gas blow micro-bulging is an novel technology to manufacture very small metal parts, in particular forbulk production. In recent years, gas blow micro-bulging have become a hot spot in thefield of microforming. In this paper, a series of experiments were carried out to studythe deformation law of gas blow micro-bulging for AZ31B magnesium alloy rolled foil. The AZ31B magnesium alloy rolled foils with0.1mm in thichness of differentgrain size were acquired through the heat treatment process at the temperature of245℃.The model of grain growth was builded by the way of regression. The foils withdifferent thichness of uniform grain size were acquired through the heat treatmentprocess at the uniform heating temperature and different healing time，the grain size isapproximately2μm. The influence of the gas pressure, bulging temperature, initial grain size, foilthickness and diameter of die cavity on formability of gas blow micro-bulging/(thebulging height/) were investigated using hemisphere free bulging tests. The experimentalresults showed that the optimum bulging temperature is380℃, in the range of forminggas pressure, the bulging height of the hemisphere parts increased with the increase ofthe forming gas pressure, the biggest bulging height of682μm and height to diameterratio of0.718were obtained at380℃、4.2MPa within15min; Using the foils whichwas subject to the heat treatment at245℃were used to study the influence of the grainsize on formability of gas blow micro-bulging, when the grain size get smaller, theformability of the gas blow micro-bulging is better and the height of hemisphere parts ishigher; When the grain size keeps constant, the thinner the thickness of foils, the higherthe bulging height; When the hemisphere parts are in good condition, the height todiameter ratio increased with the increase of the diameter of die cavity. On the ba

关 键 词： 微气压胀形 变形规律 尺寸效应 镁合金

领　　域： [金属学及工艺] [金属学及工艺] [一般工业技术] [金属学及工艺]