On Shear Testing of Single Crystal Ni-Base Superalloys

Eggeler, Gunther; Wieczorek, N.; Fox, F.; Berglund, Sean P.; Bürger, David; Dlouhý, A.; Wollgramm, P.; Neuking, K.; Schreuer, J.; Jácome, Leonardo Agudo; Gao, Siwen; Hartmaier, Alexander; Laplanche, Guillaume

doi:10.1007/s11661-018-4726-9

Cited by 7 publications

(6 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The specimens created using the presented method can also be used for many other and more detailed characterization techniques if the high‐throughput character is softened or the measurements are limited to a‐priori‐identified interesting composition ranges. This includes micro‐pillar compression, nano‐indentation and creep, in‐situ micro shear testing [ 79 ] or oxide layer stability screening by oxidation heat treatment and subsequent Raman spectroscopy.…”

Section: Resultsmentioning

confidence: 99%

A Novel Approach for Rapid Material Library Generation Using Laser‐Remelting

Gaag,

Heidowitzsch,

Galgon

et al. 2023

Adv Eng Mater

View full text Add to dashboard Cite

Cost‐ and time‐demanding trial‐and‐error methods have been the historical route for alloy development. A combinatorial approach can significantly simplify and accelerate the development process by characterization of composition dependent properties on material libraries, which are specimens or sets of specimens that map out a certain composition space, often employing composition profiles. Herein, a promising production method for such a material library is proposed: laser‐remelting of stacked blocks of different compositions is evaluated for its suitability to produce material libraries, using the ternary CrCoNi system for a proof‐of‐concept. The composition profiles of the successfully created CrCoNi material library were measured by electron probe micro analysis. The intermixing has a length of about 2.5 mm. An analytical model describing the intermixing process is proposed and shows value in the estimation of the intermixing length after the first melting step. The comparison of the experimental microstructure observations from this work and from literature shows mostly good agreement with some deviations related to microsegregation and finite quenching cooling rates, which is supported by thermodynamic calculations regarding phase stability. In the single‐phase region, the mechanical properties as measured via microhardness indentation are discussed as potential candidates for model validation.

show abstract

Section: Resultsmentioning

confidence: 99%

A Novel Approach for Rapid Material Library Generation Using Laser‐Remelting

Gaag,

Heidowitzsch,

Galgon

et al. 2023

Adv Eng Mater

View full text Add to dashboard Cite

show abstract

“…As a striking new result, it was found that from 0.5% onwards, the [112](111) shear system deforms significantly faster than the shear system [011](111), as shown in Figure 3 (see also strain vs. time data in [12]). The corresponding logarithmic shear rate plotted as a function of shear strain is presented in Figure 3b.…”

Section: Mechanical and Micro Mechanical Analysismentioning

confidence: 86%

“…After heat treatment and prior to creep, the average γ'-volume fractions were 72% and 77% in the dendritic and interdendritic regions, respectively [13,14]. In the present work, we used a shear creep test technique, which was recently documented [12]. The SX material was first mounted onto a goniometer and oriented into a specific crystallographic direction using a Laue system from Multiwire Laboratories (Lansing, NY, USA), equipped with an electronic position control unit and a sensitive real-time back reflection camera of type MWL120.…”

Section: Materials and Shear Creep Testingmentioning

confidence: 99%

“…While this reaction could be modelled using a simplified two-dimensional discrete dislocation dynamics (2D DDD) model [11], no direct experimental evidence for this reaction has been provided. In the present work, we combine high precision shear creep testing [12] with diffraction contrast scanning transmission electron microscopy (STEM) to show that these dislocation reactions govern low-temperature and high-stress SX creep.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

How Nanoscale Dislocation Reactions Govern Low- Temperature and High-Stress Creep of Ni-Base Single Crystal Superalloys

et al. 2020

View full text Add to dashboard Cite

The present work investigates γ-channel dislocation reactions, which govern low-temperature (T = 750 °C) and high-stress (resolved shear stress: 300 MPa) creep of Ni-base single crystal superalloys (SX). It is well known that two dislocation families with different b-vectors are required to form planar faults, which can shear the ordered γ’-phase. However, so far, no direct mechanical and microstructural evidence has been presented which clearly proves the importance of these reactions. In the mechanical part of the present work, we perform shear creep tests and we compare the deformation behavior of two macroscopic crystallographic shear systems [ 01 1 ¯ ] ( 111 ) and [ 11 2 ¯ ] ( 111 ) . These two shear systems share the same glide plane but differ in loading direction. The [ 11 2 ¯ ] ( 111 ) shear system, where the two dislocation families required to form a planar fault ribbon experience the same resolved shear stresses, deforms significantly faster than the [ 01 1 ¯ ] ( 111 ) shear system, where only one of the two required dislocation families is strongly promoted. Diffraction contrast transmission electron microscopy (TEM) analysis identifies the dislocation reactions, which rationalize this macroscopic behavior.

show abstract

“…Over recent years, microshear testing, which represents a kind of simple shear deformation, has received much more attention and has been studied by many researchers [85][86][87][88][89]. Metallic single crystals are widely used to perform microshear experiments because the initial crystallographic orientations of the specimens are specific and crystals with no grain boundaries have no influence on interactions with adjacent grains.…”

Section: Research On Metallic Single Crystals Under Microshearmentioning

confidence: 99%

Path Dependency of Plastic Deformation in Crystals: Work Hardening, Crystallographic Rotation and Dislocation Structure Evolution

Zhang

Liu

et al. 2022

Crystals

View full text Add to dashboard Cite

This paper reviewed the research progress of studies on the crystal rotation of single crystals that were deformed by tension and shear and the influences of crystal rotation and dislocation evolution on strain hardening behavior in crystals that were deformed with different initial orientations. The crystal rotation is entirely different depending on whether the single crystal was deformed by tension or shear. A three-stage work hardening behavior, which is not one of the intrinsic properties of materials, is generated when FCC metallic single crystals are deformed by tension along unstable oriFigurFigurentations, but single crystals do not exhibit this three-stage hardening behavior when they are deformed by simple shear at room temperature. Under tension, crystal rotation causes the transition from work hardening stage I to stage II, while the transition from work hardening stage II to III is caused by dislocation evolution. The evolution of the dislocation structure is related to deformation loading and can be classified into three types when a crystal is deformed by tension. Different from tension, shear stress can directly act on one of the 12 slip systems when a crystal is deformed by simple shear. When FCC single crystals are deformed by shear along the (11¯1)[110], (111)[112¯] and (001)[110] orientations, the single slip system, co-planar slip systems and co-directional slip systems are activated, respectively, and the crystals hardly rotate under the shear conditions. The slip direction of [110] forces the crystal to rotate toward the shear direction under simple shear. The dislocation tangles tend to form the dislocation cells and wall structures when multiple slip systems are activated under simple shear.

show abstract

On Shear Testing of Single Crystal Ni-Base Superalloys

Cited by 7 publications

References 56 publications

A Novel Approach for Rapid Material Library Generation Using Laser‐Remelting

A Novel Approach for Rapid Material Library Generation Using Laser‐Remelting

How Nanoscale Dislocation Reactions Govern Low- Temperature and High-Stress Creep of Ni-Base Single Crystal Superalloys

Path Dependency of Plastic Deformation in Crystals: Work Hardening, Crystallographic Rotation and Dislocation Structure Evolution

Contact Info

Product

Resources

About