Thermomechanical Processing and Texture Development in Ni-Cr-Mo and Mn-Mo-B Armor Steels

1984 ◽  
Author(s):  
Hsun Hu
Keyword(s):  
Thermomechanical Processing ◽  
Texture Development

Microstructure and Texture Development in Alpha-Brass Using Repetitive Thermomechanical Processing

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Khaled Al-Fadhalah
Keyword(s):  
Thermomechanical Processing ◽  
Boundary Migration ◽  
Small Strain ◽  
Texture Development ◽  
Grain Boundary Migration ◽  
Compression Tests ◽  
Brass Alloy ◽  
Electron Backscattered Diffraction ◽  
Compression Strain ◽  
Alpha Brass

Repetitive thermomechanical processing (TMP) has been applied to evaluate the effect of compression strain and temperature on microstructure and texture development in an alpha-brass alloy. Two TMP schemes were employed using four cycles of low-strain compression (ε = 0.15) and annealing, and two cycles of medium-strain compression (ε = 0.3) and annealing. Compression tests were conducted at 25, 250, and −100 °C, while annealing was made at 670 °C for 10 min. Examination by electron backscattered diffraction (EBSD) indicated that the low-strain scheme was capable to increase the fraction of Σ3n boundaries (n = 1, 2, and 3) with increasing cycles, producing maximum fraction of 68%. For medium-strain scheme, a drop in the fraction of Σ3n boundaries occurred in cycle 2. Reducing compression temperature lowered the fraction of Σ3n boundaries for low-strain scheme, while it enhanced the formation of Σ3n boundaries for medium-strain scheme. Annealing textures showed that 〈101〉 compression fiber was strongly retained for samples processed by small-strain scheme, while weakening of 〈101〉 fiber accompanied by the formation of 〈111〉 recrystallization fiber occurred for the medium-strain scheme. The results indicate that the increase in strain energy stored during compression, via increasing strain and/or decreasing deformation temperature, is responsible to favor recrystallization twinning over strain-induced grain boundary migration (SIBM). Both mechanisms are important for the formation of Σ3n boundaries. Yet, SIBM is thought to strongly promote regeneration of Σ3n boundaries at higher TMP cycles. This is consistent with the development of microstructure and texture using small-strain scheme.

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

High-resolution x-ray imaging of small copper-rich precipitates in steels

1988 ◽  
Vol 46 ◽  
pp. 528-529
Author(s):  
J. R. Michael ◽  
K. A. Taylor
Keyword(s):  
Electron Microscopy ◽  
Thermomechanical Processing ◽  
Atom Probe ◽  
Ferrite Matrix ◽  
Scanning Transmission Electron Microscope ◽  
Probe Field ◽  
X Ray ◽  
Subsequent Transformation ◽  
Transmission Electron ◽  
Scanning Transmission

Although copper is considered an incidental or trace element in many commercial steels, some grades contain up to 1-2 wt.% Cu for precipitation strengthening. Previous electron microscopy and atom-probe/field-ion microscopy (AP/FIM) studies indicate that the precipitation of copper from ferrite proceeds with the formation of Cu-rich bcc zones and the subsequent transformation of these zones to fcc copper particles. However, the similarity between the atomic scattering amplitudes for iron and copper and the small misfit between between Cu-rich particles and the ferrite matrix preclude the detection of small (<5 nm) Cu-rich particles by conventional transmission electron microscopy; such particles have been imaged directly only by FIM. Here results are presented whereby the Cu Kα x-ray signal was used in a dedicated scanning transmission electron microscope (STEM) to image small Cu-rich particles in a steel. The capability to detect these small particles is expected to be helpful in understanding the behavior of copper in steels during thermomechanical processing and heat treatment.

Structural features and strength behavior of TRIP/TWIP steels

2020 ◽  
pp. 5-18
Author(s):  
D. V. Prosvirnin ◽  
◽  
M. S. Larionov ◽  
S. V. Pivovarchik ◽  
A. G. Kolmakov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Thermomechanical Processing ◽  
Maximum Load ◽  
Structural Features ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Structural And Functional Properties ◽  
Twip Steels ◽  
The Creation

A review of the literature data on the structural features of TRIP / TWIP steels, their relationship with mechanical properties and the relationship of strength parameters under static and cyclic loading was carried out. It is shown that the level of mechanical properties of such steels is determined by the chemical composition and processing technology (thermal and thermomechanical processing, hot and cold pressure treatment), aimed at achieving a favorable phase composition. At the atomic level, the most important factor is stacking fault energy, the level of which will be decisive in the formation of austenite twins and / or the formation of strain martensite. By selecting the chemical composition, it is possible to set the stacking fault energy corresponding to the necessary mechanical characteristics. In the case of cyclic loads, an important role is played by the strain rate and the maximum load during testing. So at high loading rates and a load approaching the yield strength under tension, the intensity of the twinning processes and the formation of martensite increases. It is shown that one of the relevant ways to further increase of the structural and functional properties of TRIP and TWIP steels is the creation of composite materials on their basis. At present, surface modification and coating, especially by ion-vacuum methods, can be considered the most promising direction for the creation of such composites.

Grain Morphology and Texture Development in a Co-Cr-Mo Alloy Fabricated by Powder Bed Fusion with an Electron Beam

2019 ◽  
Author(s):  
Yufan Zhao ◽  
Yuichiro Koizumi ◽  
Kenta Aoyagi ◽  
Daixiu Wei ◽  
Kenta Yamanaka ◽  
...  
Keyword(s):  
Electron Beam ◽  
Grain Morphology ◽  
Texture Development ◽  
Powder Bed Fusion ◽  
Powder Bed

Scientific and technological bases for creation of cold-resistant steel with a guaranteed yield strength of 315–750 MPa for the Arctic. Part 2. Technology of production, structure and properties of sheet hire performance

2019 ◽  
pp. 14-41
Author(s):  
O. V. Sych
Keyword(s):  
Yield Strength ◽  
Thermomechanical Processing ◽  
The Arctic ◽  
Accelerated Cooling ◽  
Low Alloy Steels ◽  
Hot Plastic Deformation ◽  
Metal Thickness ◽  
Alloy Steels ◽  
Technology Of Production ◽  
Technological Methods

On the basis of the conducted research, a complex of scientific and technological methods has been developed for various technological processes (thermomechanical processing with accelerated cooling, quenching from rolling and separate furnace heating with high-temperature tempering). The developed method provides the formation of the structure of acceptable heterogeneity and anisotropy according to different morphological and crystallographic parameters throughout the thickness of rolled products up to 100 mm from low alloy steels with a yield strength of at least 315–460 MPa and up to 60 mm from economically alloyed steels with a yield strength of at least 500–750 MPa. The paper presents results of the industrial implementation of hot plastic deformation and heat treatment schemes for the production of cold rolled steel sheet with yield strength of at least 315–750 MPa for the Arctic. The structure of sheet metal thickness is given, providing guaranteed characteristics of strength, ductility, cold resistance, weldability and crack resistance.

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