低频振动载荷下非晶合金在微成形过程中的摩擦行为研究

发布时间：2018-02-10 17:24

本文关键词： 非晶合金微成形振动载荷摩擦双杯挤压　出处：《武汉纺织大学》2016年硕士论文　论文类型：学位论文

【摘要】：非晶合金在常温下具有优异的物理、化学以及机械性能,在过冷液相区内具备良好的微成形能力。但非晶合金微塑性成形过程中表现出几何尺寸效应,尤其是非晶坯料与模具型腔接触面间的摩擦效应会引起非晶合金流动和变形的不均匀,从而很难保证复杂微型零件的形状和尺寸精度。振动成形是一种新型的加工方式,利用振动载荷可以提高产品质量,改善界面摩擦,已经在金属和高分子材料中广泛运用。本文以锆基大块非晶合金为研究对象,利用双杯挤压工艺,对低频振动载荷作用下非晶合金在微成形过程中的摩擦行为进行了初步探究。首先利用水冷铜模吸铸法制备了实验所需的Zr55Al10Ni5Cu30大块非晶合金样品,并采用X射线衍射分析仪(XRD)和差示扫描量热仪(DSC)检测了其结构特性,确认了样品的非晶状态。设计了双杯挤压实验模型,使用Deform-2D仿真软件获得了不同振动力场作用下的摩擦标定曲线。在配备高温炉的Zwick/well材料力学性能试验机上完成了低频振动载荷作用下的双杯挤压实验,频率为0.05-2Hz,振幅为120-480,温度保持在450°C。通过三维电子显微镜测量出了样品上下杯高度值,并与模拟得到的摩擦标定曲线对照,获得了不同振动频率和振幅振动力场作用下Zr55Al10Ni5Cu30大块非晶合金微塑性成形过程中的摩擦系数。结果显示:载荷的振动频率明显地影响摩擦系数,且呈现出一定的规律性,总体上看,摩擦系数随着频率的增加而减小;对振幅而言,当振动频率为0.05和0.1Hz时,振幅的改变对摩擦系数影响不大;当振动频率为0.5Hz、1Hz、2Hz时,振幅改变对摩擦系数有一定的影响化,但是不明显,也没有像振动频率对摩擦系数影响那样有规律可循。结合非晶合金摩擦理论模型、自由体积理论和有限元模拟分析了摩擦因子随振动力场变化的原因。
[Abstract]:The amorphous alloy has excellent physical, chemical and mechanical properties at room temperature, and has good microforming ability in the supercooled liquid region. Especially, the friction effect between amorphous billet and die cavity will cause non-uniform flow and deformation of amorphous alloy, which makes it difficult to ensure the shape and dimensional accuracy of complex micro parts. Vibration forming is a new processing method. Vibration load can improve product quality and interface friction, which has been widely used in metal and polymer materials. In this paper, zirconium based bulk amorphous alloy is used as research object and double cup extrusion process is used. The friction behavior of amorphous alloy in microforming process under low frequency vibration loading was studied. Firstly, the Zr55Al10Ni5Cu30 bulk amorphous alloy samples were prepared by water-cooled copper die suction casting method. The structure characteristics of the samples were tested by X-ray diffraction analyzer (XRD) and differential scanning calorimeter (DSC-C). The amorphous state of the samples was confirmed. A double-cup extrusion model was designed. The friction calibration curves under different vibration force fields were obtained by using Deform-2D simulation software. The double cup extrusion experiments were carried out on the Zwick/well material mechanical properties test machine equipped with high temperature furnace under low frequency vibration load. The frequency is 0.05-2Hz, the amplitude is 120-480, the temperature is kept at 450 掳C. the height of the sample is measured by 3D electron microscope and compared with the friction calibration curve obtained by simulation. The friction coefficient of Zr55Al10Ni5Cu30 bulk amorphous alloy in micro-plastic forming process under different vibration frequency and amplitude vibration force field is obtained. The results show that the vibration frequency of load obviously affects the friction coefficient and presents certain regularity. On the whole, the friction coefficient decreases with the increase of frequency; for amplitude, the change of amplitude has little effect on the coefficient of friction when the vibration frequency is 0.05 and 0.1 Hz, and when the vibration frequency is 0.5 Hz, 1 Hz / 2 Hz, the friction coefficient decreases with the increase of frequency, and when the vibration frequency is 0.05 Hz and 0.1 Hz, the change of amplitude has little effect on friction coefficient. The amplitude change has a certain influence on the friction coefficient, but it is not obvious, and there is no regular rule to follow the influence of vibration frequency on the friction coefficient. Free volume theory and finite element simulation are used to analyze the reason of friction factor changing with vibration force field.
【学位授予单位】：武汉纺织大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TG139.8

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