Characterization of a Bimetallic Multilayered Composite “Stainless Steel/Copper” Fabricated with Wire-Feed Electron Beam Additive Manufacturing

Kseniya Osipovich,Denis Gurianov,Andrey Chumaevskii,Nikolai Savchenko,Nikolai Shamarin,Evgeny Kolubaev,Andrey Vorontsov

doi:10.3390/met11081151

Abstract

The results of investigating the structure and properties of multilayered bimetallic “steel–copper” macrocomposite systems, obtained by wire-feed electron beam additive manufacturing, are presented in the paper. The features of boundary formation during 3D printing are revealed when changing the filaments of stainless steel and copper. Inhomogeneities in the distribution of steel and copper in the boundary zone were detected. Interphase interaction occurs both in the steel and copper parts of the structural boundary: Cu particles with an average size of 5 µm are formed in the iron matrix; Fe particles with an average size of 10 µm are formed in the copper matrix. It was revealed that such structural elements, as solid solutions of both copper and iron, are formed in the boundary zone, with additional mutual dissolution of alloying elements and mechanical mixtures of system components. The presence of the disc-shaped precipitations randomly located in the matrix was revealed in the structure of the “copper–steel” boundary by transmission electron microscopy; this is associated with rapid cooling of alloys and the subsequent thermal effect at lower temperatures during the application of subsequent layers. The existence of these disc-shaped precipitations of steel, arranged randomly in the Cu matrix, allows us to draw conclusions on the spinodal decomposition of alloying elements of steel. The characteristics of mechanical and micromechanical properties of a bimetallic multilayered composite with a complex formed structure lie in the range of characteristics inherent in additive steel and additive copper.

Highlights

The technology of obtaining polymetallic materials has been widely studied in the last decade
The combination of different mechanical and physical–chemical properties implies a multifunctional finished product, and the complexity and, in some cases, the impossibility, of combining metals and alloys. One such example discussed in this study is the combination of C11000 copper and SS 321 stainless steel
The presence of liquid-phase separation leads to the formation of pores and cracks, which negatively affects the mechanical properties of the finished product

Summary

Introduction

The technology of obtaining polymetallic materials has been widely studied in the last decade. The combination of different mechanical and physical–chemical properties implies a multifunctional finished product, and the complexity and, in some cases, the impossibility, of combining metals and alloys One such example discussed in this study is the combination of C11000 copper and SS 321 stainless steel. Liquid-phase separation between Cu and Fe is commonly observed in laser, electron beam and arc welding processes [13] In this case, the presence of liquid-phase separation leads to the formation of pores and cracks, which negatively affects the mechanical properties of the finished product. A bimetallic multilayered composite “stainless steel/copper” was fabricated by wire-feed electron beam additive manufacturing to study the regularities of the formation of the steel–copper and copper– steel transition zone. Investigations are connected with the phenomena which occur during solidification from the liquid and solid-phase transformations

Materials and Methods

Results

Microstructure of Copper Interlayers of Zones II and IV