Effect of Temperature and Strain Rate on Deformation Mode and Crack Behavior of 7B52 Laminated Aluminum Alloy Under Impa

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Effect of Temperature and Strain Rate on Deformation Mode and Crack Behavior of 7B52 Laminated Aluminum Alloy Under Impact Loading Wenhui Liu1 · Ping Cao1 · Chenbing Zhao1 · Yufeng Song1 · Changping Tang1  Received: 10 May 2020 / Accepted: 11 August 2020 © The Korean Institute of Metals and Materials 2020

Abstract  The dynamic mechanical behaviors of 7B52 laminated aluminum alloy under different impact deformation conditions were investigated using split Hopkinson pressure bar, optical microscopy, electron backscatter diffraction and transmission electron microscopy. The results show that the 7B52 laminated aluminum alloy displays positive strain rate sensitivity and negative temperature sensitivity. Cracks are formed firstly at the interface between the 7A62 hard layer and the 7A01 middle layer under a low strain rate of 2200 s−1. When the strain rate increases to 3500 s−1, the deformation shear band is firstly formed in the 7A52 soft layer. The deformation shear band transformed to the transition shear band with the increase of strain rate, and then crack initiated. Adiabatic shear bands and cracks are formed in both of the hard and soft layers when samples impacted at a high strain rate (5500 s−1). Most of the cracks and adiabatic shear bands are unable to penetrate the middle layer due to the good toughness of the 7A01 alloy. The deformation of each layer of 7B52 laminated aluminum alloy becomes more uniform when the temperature increases, which was attributed to the reduction of difference in strength among the three layers and the coordinating effect of grain boundary on deformation. Graphic Abstract Keywords  7B52 laminated aluminum alloy · Strain rate · Dynamic mechanical properties · Microstructure · Deformation mode

1 Introduction Aluminum alloys are widely used in combat vehicles manufacture due to their advantages such as low density, high strength, good plasticity and good energy absorption capability [1–5]. To improve the protection capability against threats of armor piercing projectile, researchers have developed different series of excellent armor aluminum alloys such as Al–Cu base 2519A, Al–Mg base 5083 and * Wenhui Liu [email protected] * Changping Tang [email protected] 1



High Temperature Wear Resistant Materials and Preparation Technology of Hunan Province National Defence Science and Technology Laboratory, Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion, School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 411201, China

Al–Zn–Mg base 7039 [6–10]. However, the demand for armor materials with higher ballistic resistance becomes more and more urgent with the development of weapons. In order to meet this demand, researchers have developed novel laminated aluminum alloys in recent years. The laminated aluminum alloy is composed of different aluminum alloys with different properties, and it is usually fabricated by rolling, extrusion or other processing methods to achieve metallurgical bonding between interf