دانلود رایگان ترجمه مقاله بررسی تاثیر خواص مواد و ترتیب هر لایه بر شکل پذیری ورق های دو فلزی (نشریه الزویر 2017)

بررسی تاثیر ویژگی مواد و آرایش هر لایه، بر روی شکل پذیری ورقه های دو فلزی

Investigation into the effect of material properties and arrangement of each layer on the formability of bimetallic sheets

Abstract

The application of bimetallic sheets composed of two dissimilar sheet metals with distinct properties has increasingly developed in recent years. Enhancement of bimetallic sheet’s formability by designing of appropriate layers is an important challenge for industrialization of these sheets. The main objective of this paper is investigation on the influence of material properties of layers on the formability of bimetallic sheets analytically and experimentally. The analytical model was developed to predict forming limit diagram (FLD) based on M-K model using both the Hill’s and Barlat-Lian yield functions. The experimental works was performed on Aluminum (AL3105)/Carbon steel (St14) sheets for verification of analytical model. Results showed that the formability of bimetallic sheet is enhanced by increasing of the strain hardening and strain rate sensitivity exponents of layers, although variation of the exponent coefficient of the layer with higher formability was more effective than layer with lower formability. In addition, the results demonstrated a significant nonlinear effect of variation in thickness of layers on the FLD0 index. It is found that the influence of anisotropy coefficient of layers is negligible in comparison with other material parameters, but the arrangement of anisotropic steel layer with isotropic aluminum layer as well as the arrangement of layers in the aligned rolling direction (0°−0°) can slightly improve the formability of two-layer sheets.

1 Introduction

Recently, the application of laminated composite sheet metals and specially two-layer metallic sheets has been greatly increased due to achieving desirable mechanical, physical and chemical properties such as high strength low weight structures, vibration damping, corrosion resistance, appropriate thermal and electrical conductivity in the variant industries. Aluminum-steel (AL-St) sheet is one of the most common clad sheets, in which the cladding can be carried out by several methods such as clad rolling [1], adhesive bonding [2], explosive forming [3] and etc. These bimetallic sheets consist of two distinct metals as a high strength (St) layer bonded to a lightweight low formable (AL) layer. Therefore, their forming behavior is different that of each layer and it is worth to study the effect of material properties of each layer on the formability of two-layer sheet in order to optimum design of bimetallic sheets.

Forming limit diagram (FLD) is commonly used to evaluate the formability of sheet metals in metal forming processes. The FLD is a plot of the major strain versus the minor strain which is obtained at the onset of localized necking condition. This curve defines the maximum permissible major strain with respectto the minor strain above which failure may be occurred in the deformed sheet. The concept of FLD was introduced by Keeler [4] and Goodwin [5] for the first time in 1968. Besides of many researchers reported on the mono-sheets, the formability of two-layer sheets has been the subject of some researchers. Semiatin and Piehler[6,7] investigated the formability of stainless steel-clad aluminum and aluminumclad stainless steel sheets based on defuse and localized necking. They resulted that the final localization and fracture are affected by arrangement of layers. Mori and Kurimoto [8] studied the formability of stainless steel-aluminum clad sheet experimentally. They utilized deep drawing process with a cylindrical punch and stretch forming test with a hemispherical punch to evaluate the formability of sheet. They concluded that a higher formability can be achieved when the aluminum is set on the outer side of the cup in stretching and deep drawing tests. Yoshida and Hino [9] determined the forming limits of sheet metal laminates under biaxial stress conditions. They developed a criterion for the left hand side of the FLD curve based on the Hill’s localized necking theory. In addition, punch-stretching tests were done on two and three-ply stainless steel-clad aluminum sheets. Kim et al. [10] studied the formability of roll-bonded AA5182/polypropylene/AA5182 sandwich sheets. They used the M-K theory associated with Hill’s yield function to predict FLD of sandwich sheet.