Abstract

The influence of different types of deformation of the metal matrix on mechanical behavior of the amorphous PET film upon its transverse compression in the ductile metal matrix has been investigated. Three deformation modes have been probed. In the first case, a disc-shaped polymer specimen has been put between two 5 mm thick discs of the lead–tin alloy and squeezed in the press. In the second and the third cases, planar elongation has been performed in the so called “dead channel”, i.e., the channel with fixed side walls, the film being elongated due to decrease in the width or thickness, respectively. The plots of true yield stress at different draw ratios have formed a common master curve. At high total draw ratio Λ, the true yield stresses have been close for the considered three types of drawing in the metal. At the draw ratio Λ > 2.6, the neck has not appeared, and the specimen has been deformed uniformly. When the film in the channel is elongated due to the decrease in thickness at constant width, the specimen width has been mainly decreased during subsequent elongation in the testing machine. When the film in the channel is elongated due to the decrease in width at constant thickness, further elongation has mainly led to the decrease in the specimen thickness. The true stress Σ has been expressed as Σ = Σ₀ + KΛ³, with K being a constant. Deformation of the polymer in the channel occurred with the formation of shear bands. At the preliminary draw ratio Λ = 1.82, the bands have been oriented at the angle 21.5° with respect to the stretching axis. The planar elongation has led to abnormally strong deformation softening of the polymer. The drawing has been accompanied by an increase in the elasticity modulus of the polymer. The obtained results have suggested that the macromolecules orientation is the main reason for strain hardening of the polymer.

中文翻译：

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金属基体变形对其内部聚对苯二甲酸乙二醇酯力学性能的影响

摘要

研究了金属基体不同类型的变形对非晶 PET 薄膜在延展性金属基体中横向压缩时的机械行为的影响。已经探讨了三种变形模式。在第一种情况下，将圆盘状聚合物样本放置在两个 5 毫米厚的铅锡合金圆盘之间，并在压力机中挤压。在第二种和第三种情况下，在所谓的“死通道”（即具有固定侧壁的通道）中进行平面伸长，膜分别由于宽度或厚度的减小而被伸长。不同拉伸比下的真实屈服应力图形成了共同的主曲线。在高总拉伸比 Λ 下，所考虑的三种金属拉伸类型的真实屈服应力非常接近。在拉伸比 Λ > 2.6 时，颈部尚未出现，标本已均匀变形。当通道中的薄膜由于在恒定宽度下厚度减小而被拉长时，在随后的试验机伸长过程中，样品宽度主要减小。当通道中的薄膜由于厚度恒定而宽度减小而被拉长时，进一步的拉长主要导致样品厚度的减小。真实应力 Σ 表示为 Σ = Σ 进一步的伸长主要导致试样厚度的减小。真实应力 Σ 表示为 Σ = Σ 进一步的伸长主要导致试样厚度的减小。真实应力 Σ 表示为 Σ = Σ₀ + K Λ ³，其中K是常数。随着剪切带的形成，通道中的聚合物发生变形。在初步拉伸比 Λ = 1.82 时，带已相对于拉伸轴以 21.5° 的角度定向。平面伸长导致聚合物异常强烈的变形软化。拉伸伴随着聚合物弹性模量的增加。结果表明，大分子取向是聚合物应变硬化的主要原因。