Thermodynamic Conditions for Consolidation of Dissimilar Materials in Bimetal and Functional Graded Structures.

Alexander Khaimovich,Yaroslav Erisov,Igor Shishkovsky

doi:10.3390/ma15030825

Abstract

Functional Graded Structures and Functional Graded parts, made using dissimilar materials, are designed to provide specific properties to the final product. One of the most promising methods for manufacturing 3D Functional Graded objects is 3D laser cladding and/or direct energy deposition. However, the construction of graded and especially layered graded structures in the process of joining materials with different thermophysical properties under certain conditions is accompanied by the formation of cracks along the phase boundaries, which are a consequence of residual stresses and/or chemical segregations. The conditions for phase consolidation are macroscopic balancing of residual stresses in the region of the interface. In a broader sense, in the field of the interface, it is necessary to consider the thermodynamic equilibrium of the phases in connection with mechanical equilibrium. In this regard, the article proposed criteria for the thermodynamic affinity of phases in the area of the Functional Graded Structures interface, including the coefficients of thermal expansion and isobaric and isochoric heat capacities of the phases. Examples of cracking and the use of the obtained criteria are provided.

Highlights

Accepted: 19 January 2022Functional Graded Materials (FGMs) are in demand in changing operating conditions, which, depending on the design of the parts made from them, require corresponding variability to the characteristics of the materials [1]
With a sharp difference between the chemical composition of the FGM phases, one can speak of functional bimetallic materials (FBMs)
To solve the key problem of finding conditions for thedatabases consolidation of a multiphase calculate properties of multicomponent systems using of thermodynamic material from themodels point of view thermodynamics, we considered transfer descriptions with that wereofassessed from experimental data [24].the equation at theisinterface considering the interphase methodology based on the fact that the phasemechanical diagram isinteraction

Summary

Introduction

Functional Graded Materials (FGMs) are in demand in changing operating conditions, which, depending on the design of the parts made from them, require corresponding variability to the characteristics of the materials [1]. The extreme operating conditions include aerospace structures [2], nuclear power, and other applications that require the performance of parts at radically different temperatures [3] Material properties such as corrosion resistance, strength, toughness, wear resistance at low weight, and reasonable cost are rarely, if ever, found in a single material [4,5]. Functional Graded Structures (FGSs) and Functional Graded (FG) parts made using dissimilar materials are designed to provide specific properties to the finaltoproduct. To composite-gradient transition transition zone zone as as an an interfacial interfacial area area instead instead of of directly directly fusing fusing layers layers composite-gradient of dissimilar materials or fabricating bimetallic structures. The formation of a graded Ti6Al4V/SS304L structures with an intermediate In. V section, significant cracks wereofobtained in the interface due to the precipitation [21], during the formation a graded.

Optical

Statement

Analytic Solution

Discussion

Deviations from thethe ideal value:

Conclusions