scholarly journals Christon elastic fields in formation of bainitic ferrite lath structure

2013 ◽  
Vol 13 (01) ◽  
Author(s):  
Mikhail Kaschenko ◽  
Kerim Djemilev ◽  
Vera Chaschina
Keyword(s):  
Bainitic Ferrite ◽  
Elastic Fields ◽  
Ferrite Lath ◽  
Lath Structure

FIB and TEM Studies on the Bainitic Microstructure in Low Carbon HSLA Steels

2007 ◽  
Vol 26-28 ◽  
pp. 73-76 ◽  
Author(s):  
J.S. Kang ◽  
S.S. Ahn ◽  
C.Y. Yoo ◽  
Chan Gyung Park
Keyword(s):  
Acicular Ferrite ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Bainitic Ferrite ◽  
Granular Bainite ◽  
Low Carbon ◽  
3 Dimensional ◽  
Hsla Steels ◽  
Bainitic Microstructure ◽  
Lath Structure

In the present study, focused ion beam (FIB) technique was applied to make site-specific TEM specimens and to identify the 3-dimensional grain morphologies of bainitic microstructure in low carbon HSLA steels such as granular bainite, acicular ferrite and bainitic ferrite. Granular bainite consisted of fine subgrains and 2nd phase constituents like M/A or pearlite located at grain and subgrain boundaries. Acicular ferrite was characterized by an aggregate of ramdomly orientated and irregular shaped grains. The high angle boundaries between adjacent acicular ferrite grains caused by intragranular nucleation during continuous cooling process. Bainitic ferrite revealed uniform and parallel lath structure within the prior austenite grain boundaries and its’ packet size could effectively decreased by the formation of intragranular acicular ferrite.

Effect of Cooling Procedure on Tensile and Charpy Impact Properties of Cr-Mo Ultra-High Strength Steel

2015 ◽  
Vol 816 ◽  
pp. 761-768 ◽  
Author(s):  
Hui Xie ◽  
Lin Xiu Du ◽  
Jun Hu
Keyword(s):  
Tensile Strength ◽  
Yield Strength ◽  
Impact Energy ◽  
Bainitic Ferrite ◽  
Charpy Impact ◽  
High Strength ◽  
Coiling Temperature ◽  
Lath Bainite ◽  
Ferrite Lath ◽  
Cooling Procedure

The effect of cooling procedure on the transformation behavior of low-carbon Cr-Mo microalloyed steel was investigated by using microstructural observations, mechanical properties and impact fractographs. Three steel plates were adopted under three different cooling rates, and their microstructure, tensile and impact properties were evaluated. The results indicated that the strength of experimental steels was increased and the impact toughness was decreased with decreasing the coiling temperature. Steel A consisted of granular bainite, coarse bainitic ferrite lath and M/A constituent subjected to a coiling temperature of 560 oC. The yield strength, tensile strength and impact energy of 1/2-size Charpy impact at-20 oC were 740MPa, 1020MPa, and 33.5J, respectively, which were imperfect in strength. The effects of coiling temperature were potent on the refinement of microstructure and the size of M/A constituents. Steel B consisted of a small amount of lath bainite, fine M/A constituents and bainitic ferrite lath subjected to a lower coiling temperature of 520 oC. The yield strength, tensile strength and impact energy of 1/2-size Charpy impact at-20°C were 840MPa, 1030MPa, and 30.7J, respectively. However, steel C was composed of lath bainite and lath martensite subjected to the lowest coiling temperature of 380 oC (slightly above Ms point). The yield strength, tensile strength and impact energy of 1/2-size Charpy impact at-20 oC were 985MPa, 1200MPa and 22.5J, respectively, which could meet the demand of ultra high strength structural steel applications.

Effects of Warm Working on Microstructural and Shear Deformation Properties of TRIP-Aided Martenitic Steel

2016 ◽  
Vol 879 ◽  
pp. 2312-2317
Author(s):  
Tomohiko Hojo ◽  
Takuya Kochi ◽  
Koh Ichi Sugimoto
Keyword(s):  
Shear Deformation ◽  
Retained Austenite ◽  
Maximum Shear Stress ◽  
Effective Strain ◽  
Bainitic Ferrite ◽  
Ferrite Matrix ◽  
Warm Working ◽  
Deformation Properties ◽  
Ferrite Lath ◽  
Constituent Phase

The effects of warm working on microstructural, retained austenite characteristics and shear deformation properties of 0.2C–1.5Si–1.5Mn–1.0Cr–0.2Mo TRIP-aided martensitic (TM) steel for applications to automotive frame and forging parts were investigated. When warm working at 550 °C and post cooling at 1 °C/s was conducted to the TM steel, volume fractions of retained austenite and martensite-austenite constituent phase increased and mixture matrix of ultra fine granular bainitic ferrite and fine bainitic ferrite lath was obtained, whereas microstructure of TM steel warm worked at 750 °C exhibited granular bainitic ferrite matrix. These were caused by the dynamic recrystallization and the promotion of bainitic transformation of austenite due to the worm forging at 550 °C with the post cooling rate of 1 °C/s. Maximum shear stress decreased and total shear displacement increased with decreasing working temperature in TM steel. These were caused by the effective strain induced transformation of a large amount of retained austenite and the refined matrix structure.

New Insights into Carbon Distribution in Bainitic Ferrite

2018 ◽  
Vol 73 (2) ◽  
pp. 68-79 ◽  
Author(s):  
R. Rementeria ◽  
C. Garcia-Mateo ◽  
F. G. Caballero
Keyword(s):  
Bainitic Ferrite ◽  
Carbon Distribution

scholarly journals Nonlocal elastodynamics and fracture

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Robert P. Lipton ◽  
Prashant K. Jha
Keyword(s):  
Field Theory ◽  
Brittle Fracture ◽  
A Priori ◽  
Nonlocal Model ◽  
Elastic Fields ◽  
Nonlocal Field Theory ◽  
Nonlocal Field ◽  
Increasing Function ◽  
Non Locality

AbstractA nonlocal field theory of peridynamic type is applied to model the brittle fracture problem. The elastic fields obtained from the nonlocal model are shown to converge in the limit of vanishing non-locality to solutions of classic plane elastodynamics associated with a running crack. We carry out our analysis for a plate subject to mode one loading. The length of the crack is prescribed a priori and is an increasing function of time.

Structural Changes in a 9%Cr Creep Resistant Steel during Creep Test

2012 ◽  
Vol 715-716 ◽  
pp. 895-900
Author(s):  
Valeriy Dudko ◽  
Andrey Belyakov ◽  
Vladimir Skorobogatykh ◽  
Izabella Schenkova ◽  
Rustam Kaibyshev
Keyword(s):  
Structural Changes ◽  
Subgrain Size ◽  
Large Strain ◽  
Particle Growth ◽  
Second Phase ◽  
Second Phase Particles ◽  
Creep Rupture Test ◽  
Lath Structure ◽  
Creep Regime ◽  
Effective Stabilization

Structural changes in a 9%Cr martensitic steel after 1%, 4% creep and creep rupture test at 650°C and stress of 118 MPa were examined. Heat treatment provided the formation of tempered martensite lath structure (TMLS) in the steel. The precipitations of second phase particles along block and lath boundaries provide effective stabilization of the TMSL under annealing/aging condition. This structure hardly changed under creep conditions in grip portion of crept sample. Significant coarsening of both the second phase particles and the martensite laths takes place in neck portion. In addition, the latter ones lose their original morphology and are replaced by large strain-induced subgrains. It should be noted that the increase of subgrain size is in almost direct proportion to the particle growth during the creep to 4% strain. The rapid growth of martesite laths followed by their evolution to deformation subgrains takes place within the tertiary creep regime.

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