scholarly journals Ferrite recrystallization and austenite formation during annealing of cold-rolled advanced high-strength steels: In situ synchrotron X-ray diffraction and modeling

2019 ◽  
Vol 154 ◽  
pp. 20-30 ◽  
Author(s):  
Marion Bellavoine ◽  
Myriam Dumont ◽  
Moukrane Dehmas ◽  
Andreas Stark ◽  
Norbert Schell ◽  
...  
Keyword(s):  
High Strength Steels ◽  
High Strength ◽  
Austenite Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Advanced High Strength Steels ◽  
Cold Rolled

scholarly journals In Situ Determination of Phase Stress States in an Unstable Medium Manganese Duplex Steel Studied by High-Energy X-ray Diffraction

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1335
Author(s):  
Mathias Lamari ◽  
Sébastien Y. P. Allain ◽  
Guillaume Geandier ◽  
Jean-Christophe Hell ◽  
Astrid Perlade ◽  
...  
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
High Energy ◽  
Internal Stresses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Advanced High Strength Steels ◽  
Stress States

Duplex medium Mn steels are high-potential advanced high-strength steels (AHSS) for automotive construction. Their excellent forming properties stem from the specific stress partitioning between their constituting phases during deformation, namely the ferritic matrix, unstable retained austenite, and strain-induced fresh martensite. The stability of the retained austenite and the 3D stress tensors of each phase are determined simultaneously in this work by in situ high energy X-ray diffraction on synchrotron beamline during a tensile test. The role of internal stresses inherited from the manufacturing stage are highlighted for the first time as well as new insights to understand the origin of the serrations shown by these alloys.

Influence of the Processing Variables on the Microstructure Evolution of a Bainitic Carbide-Free Steel

2016 ◽  
Vol 879 ◽  
pp. 867-872 ◽  
Author(s):  
M.C. Taboada ◽  
I. Gutiérrez ◽  
D. Jorge-Badiola ◽  
S.M.C. van Bohemen ◽  
F. Hisker ◽  
...  
Keyword(s):  
Retained Austenite ◽  
High Strength Steels ◽  
High Strength ◽  
High Volume ◽  
X Ray Diffraction ◽  
Tempered Martensite ◽  
Trip Steels ◽  
Volume Fractions ◽  
Advanced High Strength Steels ◽  
Processing Variables

New trends focused on achieving higher performance steels has led to a so-called 3rd Generation Advanced High Strength Steels (AHSS), in which the typical polygonal ferrite found in TRIP steels as a matrix phase is replaced by harder phases as Carbide-Free Bainite (CFB) and/or (tempered) martensite. Besides, large volume fractions of retained austenite (R.A.) with adequate stability are aimed for to improve the formability of the steels. Si containing steels are regarded as the most suitable to retard cementite formation and consequently reach high volume fractions of RA. In this work, CFB annealing schedules were applied to dilatometer samples of Fe-0.22C-2.0Mn-1.3Si. The overaging temperature TB was varied between 390 oC and 480 oC, and other processing variables investigated were the austenitizing temperature Taus, and the overaging holding time tB. The annealed samples analyzed with LOM, FEG-SEM, EBSD and X-ray diffraction techniques show that markedly different complex microstructures made up of bainite, ferrite, MA phase and retained austenite (R.A) are accomplished depending on the specific thermal cycle. These results are described in detail and discussed in relation to the dilatometry measurements.

X-Ray Residual Stress Measurement on Stress Corrosion Fracture Surfaces

1992 ◽  
Vol 36 ◽  
pp. 543-549
Author(s):  
Masaaki Tsuda ◽  
Yukio Hirose ◽  
Zenjiro Yajima ◽  
Keisuke Tanaka
Keyword(s):  
Fracture Toughness ◽  
Residual Stress ◽  
Fracture Surface ◽  
Stress Corrosion ◽  
Stress Measurement ◽  
High Strength Steels ◽  
High Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Fracture Surfaces

X-ray fractography is a new method utilizing the X-ray diffraction technique to observe the fracture surface for the analysis of the micromechanisms and mechanics of fracture. X-ray residual stress has been confirmed to be a particularly useful parameter when studying the fracture surfaces of high strength steels. The method has been applied to the fracture surface of fracture toughness and fatigue specimens.

X-ray Residual Stress Measurement on Fracture Surface of Stress Corrosion Cracking

1989 ◽  
Vol 33 ◽  
pp. 327-334 ◽  
Author(s):  
Masaaki Tsuda ◽  
Yukic Hirose ◽  
Zenjiro Yajima ◽  
Keisuke Tanaka
Keyword(s):  
Fracture Toughness ◽  
Residual Stress ◽  
Fracture Surface ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Stress Measurement ◽  
High Strength Steels ◽  
High Strength ◽  
X Ray Diffraction ◽  
X Ray

X-ray fractography is a new method utilizing the X-ray diffraction technique to observe the fracture surface for the analysis of the micromechanisms and mechanics of fracture. The X-ray residual stress has been confirmed to be a particularly useful parameter when studying the fracture surfaces of high strength steels. The method has been applied to the fracture surface of fracture toughness and fatigue specimens.

scholarly journals Spot Weld Strength Determination Using the Wedge Test: In Situ Observations and Coupled Simulations

2010 ◽  
Vol 24-25 ◽  
pp. 299-304 ◽  
Author(s):  
Rémi Lacroix ◽  
Joël Monatte ◽  
Arnaud Lens ◽  
Guillaume Kermouche ◽  
J.M. Bergheau ◽  
...  
Keyword(s):  
Energy Analysis ◽  
High Strength Steels ◽  
High Strength ◽  
Spot Weld ◽  
Weld Strength ◽  
Spot Welds ◽  
Local Loading ◽  
Advanced High Strength Steels ◽  
Strength Determination

This paper describes an innovative way to characterize the strength of spot welds. A wedge test has been developed to generate interfacial failures in weldments and observe in-situ the crack propagation. An energy analysis quantifies the spot weld crack resistance. Finite Element calculations investigate the stresses and strains along the crack front. A comparison of the local loading state with experimentally observed crack fronts provides the necessary data for a failure criterion in spot weld fusion zones. The method is applied to spot welds of Advanced High Strength steels.

A Technique for Brazing Aluminum Nitride Substrates

1989 ◽  
Vol 167 ◽  
Author(s):  
M. Grant Norton ◽  
Jacek M. Kajda ◽  
Brian C. H. Steele
Keyword(s):  
Aluminum Nitride ◽  
High Strength ◽  
Lead Frame ◽  
Reaction Products ◽  
X Ray Diffraction ◽  
X Ray ◽  
Iron Nickel ◽  
In Situ Decomposition ◽  
Nickel Lead

AbstractA technique for brazing aluminum nitride (AIN) using conventional (non-active) brazing alloys has been investigated. The process involves the in-situ decomposition of a metal hydride. This process alters the surface chemistry of the substrate and improves the wettability of the molten braze. The development of high strength bonding between braze and ceramic results. The ceramic-braze interface was studied using scanning electron microscopy (SEM). The nature of the interfacial reactions and the reaction products have been identified using x-ray diffraction (XRD). The progress of the reaction has been followed using differential thermal analysis (DTA).The experimental results have been correlated with thermodynamic predictions of the reaction process. In addition to joining ceramic to ceramic, braze joints of AIN to a low expansion iron-nickel lead frame alloy were made.

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