Interface Quality Indices of Al–10Si–Mg Aluminum Alloy and Cr18–Ni10–Ti Stainless-Steel Bimetal Fabricated via Selective Laser Melting

Alexander Khaimovich,Yaroslav Erisov,Alexander Kuzin,Viktoriya Kokareva,Anton Agapovichev,Vitaliy Smelov,Ilia Petrov,Igor Bobrovskij,Vasilii Razhivin

doi:10.3390/met11010172

Abstract

Bimetallic materials are important in many industries (aerospace, medicine, etc.) since they allow the creation of constructions that combine specific functional properties, for example, low density (aluminum alloy) and high corrosion resistance (stainless steel), due to layering fabrication of the bimetallic joint. On the other hand, the difference in thermophysical properties of the dissimilar material layers leads to residual stresses, which cause deformation and destruction of such a bimetallic joint produced via the methods of surfacing or additive technologies. This article discusses the methods based on the gray relational analysis and generalized desirability function for the quality assessment of Al–10Si–Mg aluminum alloy and Cr18–Ni10–Ti stainless-steel bimetal fabricated via selective laser melting (SLM). There are four main parameters (quality indices) of the quality generalized assessment, which determine the degree of Al penetration into the steel substrate and Fe into the deposited layer, the difference in microhardness values on both sides of the interface boundary, and the resistance to mechanical destruction of the bimetallic joint. According to the results obtained, the best set of quality indices corresponds to the SLM technological modes with an energy density of 105 and 147 J/mm3. The greatest functionality of the bimetals is determined by the quality index associated with its strength. Therefore, methods of gray relational analysis and desirability function make it possible to form a generalized assessment for the bimetallic joint quality and, consequently, to select the best technological mode.

Highlights

Bimetallic materials are widely used in the medical and aerospace industries, for example, in the fabrication of bimetallic interfaces in joints, where it is necessary to switch from one material to another in a limited space
Bimetallic materials are a type of functional-gradient material (FGM)
In FGMs, both the composition and the structure gradually change over the volume, resulting in corresponding changes in the material properties

Summary

Introduction

Bimetallic materials are widely used in the medical and aerospace industries, for example, in the fabrication of bimetallic interfaces in joints, where it is necessary to switch from one material to another in a limited space (for example, stainless steel–aluminum alloy interfaces in pneumatic hydraulic systems of launch vehicles).Bimetallic materials are a type of functional-gradient material (FGM). A separate class of FGMs is made up of metallic layered materials (bimetals) and materials with a large gradient of the composition ingredients in the interface area These materials include bimetallic compounds such as stainless steel–aluminum alloy and stainless steel–copper alloy and are widely used in the aerospace industry. The aim of this research was to develop and test criteria and methods for quantitatively assessing the structural heterogeneity in the interfacial zone and to explore the structural gradient along the thickness direction. These evaluation criteria are necessary to select the optimal technological modes for obtaining a bimetallic material with required functional properties

Objectives

Methods

Results

Conclusion