The Formation and Evolution of Shear Bands in Plane Strain Compressed Nickel-Base Superalloy

Abstract

The formation and evolution of shear bands in Inconel 718 nickel-base superalloy under plane strain compression was investigated in the present work. It is found that the propagation of shear bands under plane strain compression is more intense in comparison with conventional uniaxial compression. The morphology of shear bands was identified to generally fall into two categories: in "S" shape at severe conditions (low temperatures and high strain rates) and "X" shape at mild conditions (high temperatures and low strain rates). However, uniform deformation at the mesoscale without shear bands was also obtained by compressing at 1050 • C/0.001 s −1 . By using the finite element method (FEM), the formation mechanism of the shear bands in the present study was explored for the special deformation mode of plane strain compression. Furthermore, the effect of processing parameters, i.e., strain rate and temperature, on the morphology and evolution of shear bands was discussed following a phenomenological approach. The plane strain compression attempt in the present work yields important information for processing parameters optimization and failure prediction under plane strain loading conditions of the Inconel 718 superalloy.dangerous factor for deformation and may result in localized deformation and local failure. It not only can significantly degrade the mechanical properties of alloys, but also can lead to the final failure of the component due to the shear-induced cracking. Therefore, a new insight of the flow characteristics at various deformation conditions during hot-working process is of great importance in controlling deformation, and contributing to obtain desirable components.Up to now, many studies focused on the flow instability of alloys by means of isothermal uniaxial compression [10][11][12]. However, only few investigations primarily concerned with the flow behavior under the plane strain compression [13]. In the present study, the deformation behavior of Inconel 718 superalloy in generalized plane strain conditions subjected to pressure and elevated temperature is investigated and discussed. The effect of processing parameters on shear band propagation and unstable plastic was studied by analyzing the flow curves and microstructures. Furthermore, the finite element method (FEM) [14,15] was employed to interpret the occurrence and evolution of shear bands during the compression process. The present work for Inconel 718 superalloy yields important information for the optimizing of processing parameters and failure prediction under plane strain conditions.

Photoelastic characterization of shear‐bands in mechanically stretched polymeric fibers

“…In terms of energy, in homogeneous processes such as shear bands and crazing would absorb energy (Donald & Kramer, 1982). This knowledge enhances the design of new materials and increases the endurance of existing materials to extreme working conditions, which is the focus of recent research activities (Tang et al, 2018;Viswanathan, Yadav, & Sagapuram, 2020;Wang et al, 2018).…”

“…The evolution of the shear bands depends on the mobility of the dislocations at the boundaries of the banded structure. The result is a confined regions of a localized shearing strain in the shape of the latter "X" due to severe plastic deformation of ductile polymers (Tang et al, 2018).…”

A Review on Strain Gradient Plasticity Approaches in Simulation of Manufacturing Processes

“…During machining, for example, material is removed from the work piece by inducing large amounts of shear in localized areas called Shear Bands (SBs) (see Figure 1). Due to the high speed of the process (cutting velocities up to 90 m/s) [12][13][14][15], high strain rates (10 5 s −1 ) are induced in the SBs [16][17][18]. The high levels of stresses and strains give rise to plastic deformations, therefore inducing softening in the material at this same location.…”

“…In Figure 2, the crystallographic analysis during a FSW process highlights the modification of the grain size and orientation induced during manufacturing. Shear bands have been reported to appear also during a high-temperature compression test on Nickel super-alloy [15]. On top of the already complex scenario, at the location where the applied forces are transferred from the tool to the workpiece, the material experiences complex behaviors as well.…”

Aspects of High Strain Rate Industrial Forging of Inconel 718

“…For instance, some materials exhibit drastic softening that leads to the formation of macroscopic shear bands, dead zones, etc. [8,9]. The most promising way to resolve this problem is to gain a better understanding of the nature of material behaviour at the microscopic level, which is possible from a material science approach described below.…”