A multi-scale approach to investigate the nonlinear subsurface behavior and strain localization of X38CrMoV5-1 martensitic tool steel: Experiment and numerical analysis

Abstract

The cyclic mechanical behavior, the wear and fatigue resistances and damage developments of working surface of tool steels are dependent on microstructural features. A multi-scale approach combining experimental testing, numerical treatments and simulations is developed to model the surface behavior of X38CrMoV5-1 martensitic tool steels. The multi-scale modeling is coupled with finite element calculations. The elasto-viscoplastic constitutive equations used are based on crystal plasticity model of Méric-Cailletaud and are implemented on the finite element code ABAQUS under a small strain assumption. Trough an appropriate laboratory testing, the microstructure features comparable to the surface of industrial tools or pin/disc in tribology experiments are reproduced by considering plate specimens. Monotonic tensile testing is coupled with in-situ Digital Image Correlation technique (DIC) to determine the surface strain fields. The measured local nonlinear mechanical strain fields are analyzed. The strain localization is related to stereological artifacts. The numerical treatments allow reproducing, qualitatively, the strain localization patterns at the surface observed during tensile testing. The influence of the various stereological parameters such as the morphology of martensitic laths, the crystallographic orientations, the internal hardening state of the surface profiles and their evolutions on the local strain fields are addressed. By such approach, it is possible to get a better insight of some elementary mechanisms acting on tools and/or pin/disc surfaces regarding both tensile and cyclic behavior.

Finite element modeling and simulation of vacuum brazing processes with a focus on cycle-dependent component distortion

“…In addition to processing strategies such as the use of brazing foils with a ductile interlayer made of copper, simulation-based optimization of the process is usually applied for this purpose [9][10][11][12][13]. On the other hand, there are assemblies with integrated cooling channels at the joint level, primarily in toolmaking, for which distortion leads to leakage and thus to the failure of the component [12,14]. An example that illustrates these relationships quite well is a brazed component from EUV-lithography which is important to manufacture latest generation semiconductors and CPU cores in the nm range [15].…”

A Multi-Scale Tool Orientation Generation Method for Freeform Surface Machining with Bull-Nose Tool

“…Multi-scale methods have been widely used in various fields. For example, they have been used in metal materials to study the surface behavior of martensitic tool steels [ 16 ] and in geometric modeling to establish geometrical simulation models [ 17 ]. In the research on surface topography, multi-scale methods have been used to analyze the surface morphology of workpieces and to realize more precise machining control and surface optimization [ 18 , 19 ].…”

Effect of Elevated Temperatures on Mechanical Properties of Ultra High Strength Hot Work Tool Steel H11

“…However, the pressures to which the tool material is exposed are still very high, which results in the trend to select the highest quality material possible for the manufacture of such tools. Such materials must possess high consistency at elevated temperatures, primarily of tensile properties and resistance to crack initiation [5][6][7][8][9][10]. This was the reason that led to setting the objective of this study, which is the influence of temperature increase on mechanical properties of the considered steel as well as the ultimate temperature to which the steel could be heated without jeopardizing the tool integrity during forging.…”

“…They recorded stress amplitudes, plastic strain amplitudes and mean stresses in terms of the number of loading cycles. On the other hand, it is interesting to become familiar with the behaviour of this steel during crack initiation and propagation, which is also the research subject [5,6].…”