【作者】 童敏杰；

【导师】 张凯锋；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2006， 硕士

【摘要】 随着微机电系统的高速发展,微型零件的需求越来越迫切,微塑性成形技术作为微加工的一种,已成为塑性加工学界和业界的研究热点。其中,材料对微塑性成形技术的影响和微塑性成形过程中的尺寸效应成为微塑性成形研究的基本问题。本文通过采用电沉积方法制备了适合微塑成形的细晶薄铜板,并对其单向拉伸时的尺寸效应和微成形性能进行了研究。利用脉冲电沉积方法制备了不同厚度的薄铜板。SEM表面观察表明,晶粒大小均匀,材料致密。经过热处理后,得到了不同晶粒大小的薄铜板。对所制备的薄铜板进行了室温拉伸实验,研究薄铜板在不同晶粒大小、不同板厚和不同应变速率下的尺寸效应。实验表明,晶粒越小,铜板的厚度越大,材料的延伸率和强度越高;材料力学性能对应变速率不敏感。引入多晶体表面层模型来解释微塑性成形中流动应力的尺寸效应规律,通过晶粒内部和晶界之间变形的均匀性来解释微塑性成形中延伸率的尺寸效应规律。对所制备的薄铜板进行了高温拉伸实验,研究了薄铜板在高温下的力学性能和尺寸效应。对所制备的薄铜板进行了板的厚度和凹模直径、圆角成正比的高温胀形实验,考察了不同胀形直径下的最大胀形力和高径比两个指标,得出最大胀形力和高径比都随着凹模直径增加而增加的结论,对不同的胀形部位进行了组织观察。对所制备的薄铜板进行了室温拉深实验,制备了直径为1mm,高度为0.6mm的拉深件。更多还原

【Abstract】 With the rapid development of the micro electro mechanical systems, the requirements of microparts become more and more urgent. As one of micro manufacture ways, research of the technology of micro forming has been the hot point of plastic forming. The infection of material to micro-forming and the size effect in micro-forming has been the basic problems in the research of micro-forming. In this paper, a thin copper sheet of fine crystal which is adapt to micro-forming is made by electrodeposition method. The size effect in its simple tension and its micro-forming ability is researched.In this paper, we used pulse electrodeposition method to prepare a different thickness thin copper sheet. SEM study of copper surface shows that the crystal size is uniformity and material is coMPaction. After heat treating, the thin copper sheet whit different crystal size is got.The tension test at room temperature is used to study the size effect of thin copper sheet with different crystal size, different thickness and different strain rate. The result shows that whit the reduce of crystal size and the increase of thickness, material’s elongation percentage and strength is become more and more higher; and material is not sensitive to the strain rate. The free surface layer model is founded to explain the size effect of the flow stress in micro forming. The uniformity of deformation between inter grain and grain boundary is used to explain the size effect of elongation percentage in micro forming. The high temperature tension test is used to research material’s mechanic property at high temperature.A high temperature bulging test of the thin copper sheet is processed to study the biggest bulging force and the ratio of the bulging height and the diameter of female die when the diameter of bulging female die is different. In this test the thickness of the thin copper sheet, the diameter of female die and the rounding angle of female die is of direct ratio. The result shows that the biggest bulging force and the ratio of the bulging height and the diameter of female die is increased with the increase of the diameter of female die. The deep drawing test is processed at room temperature. A deep drawing part with diameter 1mm and更多还原