Comparison of the Threshold Stress Intensities and Fracture Characteristics for Temper Embrittled and Deembrittled 2[fraction one-quarter] Cr-1M0 Steel in a Hydrogen Charging Environment

2009 ◽  
pp. 351-351-12 ◽  
Author(s):  
GE Hicho ◽  
CM Gilmore
Keyword(s):  
Threshold Stress ◽  
Fracture Characteristics ◽  
Hydrogen Charging

Comparison of Behaviour of Different Variants of Hydrogenated TRIP Steels at Slow Strain Rate Tests

2019 ◽  
Vol 810 ◽  
pp. 70-75
Author(s):  
Petra Váňová ◽  
Jaroslav Sojka ◽  
Kateřina Konečná ◽  
Taťána Radkovská
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Absorption ◽  
Potassium Thiocyanate ◽  
Tensile Tests ◽  
Fracture Characteristics ◽  
Trip Steels ◽  
Hydrogen Charging ◽  
Metallic Inclusions ◽  
Significant Difference ◽  
Fracture Micromechanism

The paper describes effect of hydrogen on mechanical properties and fracture characteristics of two types of C-Mn-Si TRIP steel; laboratory prepared steel TRIP 800 and commercially manufactured steel TRIP 780. TRIP steels are very promising materials thanks to their combination of a very good strength and toughness. However, these steels can be embrittled by hydrogen during technological operations related to galvanizing. That is why the knowledge of effects of hydrogen on the properties and fracture characteristics of the TRIP steels is of particular importance. In the presented study, effects of hydrogen were studied by tensile tests after electrolytical hydrogen charging. Electrolytical hydrogen charging was performed in 0.05 M solution of sulfuric acid with addition of potassium thiocyanate to promote hydrogen absorption. Hydrogen provoked embrittlement in both steel variants and changed their fracture micromechanism. Hydrogen embrittlement manifested itself mainly by a loss of plasticity. Index of hydrogen embrittlement, expressed on the basic of a relative drop of elongation to fracture, reached values about 77 % for the steel variant TRIP 800, resp. 83 % for the steel variant TRIP 780. No significant difference was observed between two steel variants studied. Concerning fractographic characteristics, steels containing hydrogen displayed quasi-cleavage fracture mostly on the edges of the sample and around elongated non-metallic inclusions.

scholarly journals Influence of Strain Rate on Fracture Characteristics and Diffusible Hydrogen of High Tensile Steel under Hydrogen Charging

2019 ◽  
Vol 68 (2) ◽  
pp. 46-52 ◽  
Author(s):  
Gaku Kitahara ◽  
Aya Tsuji ◽  
Takashi Asada ◽  
Tomohiro Suzuki ◽  
Keitaro Horikawa ◽  
...  
Keyword(s):  
Strain Rate ◽  
Diffusible Hydrogen ◽  
Fracture Characteristics ◽  
Hydrogen Charging

Electron Microscopy of Metal-Matrix Composites

1970 ◽  
Vol 28 ◽  
pp. 404-405
Author(s):  
A. Lawley ◽  
M. R. Pinnel ◽  
A. Pattnaik
Keyword(s):  
Electron Microscopy ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Critical Evaluation ◽  
Elastic Behavior ◽  
Matrix Composites ◽  
Directionally Solidified ◽  
Fracture Characteristics ◽  
Broad Program

As part of a broad program on composite materials, the role of the interface on the micromechanics of deformation of metal-matrix composites is being studied. The approach is to correlate elastic behavior, micro and macroyielding, flow, and fracture behavior with associated structural detail (dislocation substructure, fracture characteristics) and stress-state. This provides an understanding of the mode of deformation from an atomistic viewpoint; a critical evaluation can then be made of existing models of composite behavior based on continuum mechanics. This paper covers the electron microscopy (transmission, fractography, scanning microscopy) of two distinct forms of composite material: conventional fiber-reinforced (aluminum-stainless steel) and directionally solidified eutectic alloys (aluminum-copper). In the former, the interface is in the form of a compound and/or solid solution whereas in directionally solidified alloys, the interface consists of a precise crystallographic boundary between the two constituents of the eutectic.

The effects of strain and strain rate on residual microstructures in copper

1986 ◽  
Vol 44 ◽  
pp. 420-421
Author(s):  
M. F. Stevens ◽  
P. S. Follansbee
Keyword(s):  
Strain Rate ◽  
Applied Stress ◽  
Threshold Stress ◽  
Rate Sensitivity ◽  
Viscous Drag ◽  
Strain Rates ◽  
Strain And Strain Rate ◽  
Threshold Strength ◽  
Mechanism Transition ◽  
Intrinsic Strength

The strain rate sensitivity of a variety of materials is known to increase rapidly at strain rates exceeding ∼103 sec-1. This transition has most often in the past been attributed to a transition from thermally activated guide to viscous drag control. An important condition for imposition of dislocation drag effects is that the applied stress, σ, must be on the order of or greater than the threshold stress, which is the flow stress at OK. From Fig. 1, it can be seen for OFE Cu that the ratio of the applied stress to threshold stress remains constant even at strain rates as high as 104 sec-1 suggesting that there is not a mechanism transition but that the intrinsic strength is increasing, since the threshold strength is a mechanical measure of intrinsic strength. These measurements were made at constant strain levels of 0.2, wnich is not a guarantee of constant microstructure. The increase in threshold stress at higher strain rates is a strong indication that the microstructural evolution is a function of strain rate and that the dependence becomes stronger at high strain rates.

Effect of the Electro-Chemical Hydrogen Charging Time on Hydrogen Embrittlement of X70 Steel Using for Gas Pipeline

2013 ◽  
Vol 51 (11) ◽  
pp. 813-820
Author(s):  
Chi-Eun Sung ◽  
Hyeon-Jee Jeon ◽  
Jin-Kyung Lee ◽  
In-Soo Son ◽  
Sang-Pill Lee ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
Gas Pipeline ◽  
Hydrogen Charging ◽  
Charging Time
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