Effect of Severe Cold-Rolling and Subsequent Annealing on Microstructure and Properties of in-Situ Composite Steel

2010 ◽  
Vol 667-669 ◽  
pp. 157-160
Author(s):  
Jun Zhao ◽  
Han Zhang ◽  
Yong Ming Yang ◽  
Jiu Chuan Chen ◽  
Quan Xing Wen ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Lath Martensite ◽  
Rolling Plane ◽  
Subsequent Annealing ◽  
Rolled Sample ◽  
In Situ Composite ◽  
Cold Rolling And Annealing ◽  
Cold Rolled ◽  
Equiaxed Grains

In this paper, the process of severe cold-rolling and annealing for Q235 steel with lath martensite has demonstrated a new promising technique for producing in-situ composite multi-nanolayer steel. Cold rolling and subsequent annealing have great impact on microstructure evolution as well as mechanical properties. In the as-rolled state, the strength (b 2112 MPa) is approximately four times increased than as-received material, which is attributed to work hardening and grain refining during cold rolling. As cold-rolled sample subjected to further annealing below 500 °C, deformed microstructure underwent further recovery and recrystallization and finally became refined equiaxed grains; ultrafine ferrite grains, nano-carbides precipitated uniformly were seen in the specimen annealed at 500 °C, and the phenomenon of fracture delamination was observed from the specimens, the delamination plane was parallel to the rolling plane, in-situ composite weak interfaces effect has great impact on the fracture surface. Annealing at and above 600 °C resulted in coarse ferrite grains with spheroidized coarse carbides, causing grain growth.

Microstructure Characteristics and Mechanical Properties of in-Situ Composite Steel Processed by Severe Cold-Rolling and Subsequent Annealing

2010 ◽  
Vol 168-170 ◽  
pp. 889-894
Author(s):  
Jun Zhao ◽  
Zhi Wang ◽  
Han Zhang ◽  
Hong Yan Zhai ◽  
Quan Xing Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Lath Martensite ◽  
Rolling Direction ◽  
High Strength ◽  
Subsequent Annealing ◽  
Microstructure Characteristics ◽  
In Situ Composite ◽  
Cold Rolled

In this paper, Q235 steel was investigated in order to manufacturing ultra-high strength material. The process of severe cold-rolling and low temperature annealing of lath martensite effectively reduced the crystal size from about 300 nm to 20 nm, and introduced mass weak interfaces in steel, has been demonstrated a new promising technique for producing in-situ composite multi-nanolayer steel with ultra-high strength (b 2112 MPa). Cold rolling and subsequent annealing have great impact on microstructure evolution as well as material mechanical properties. In the as-rolled state, the strength is approximately four times increased than as-received material (hot-rolled state, b 515 MPa), which is attributed to work hardening and grain refining during cold rolling. As the cold-rolled sample subjected to further annealing below 500 , deformed microstructure underwent further recovery and recrystallization, finally became refined equiaxed grains, microstructure characteristics along rolling direction arrangement was decreased; In addition to ultrafine ferrite grains, nano-carbides precipitated uniformly in the specimen annealed at 500 , total elongation increased to 16%, the corresponding yield strength was 1208MPa, much higher than that of as-received samples. The phenomenon of fracture delamination was observed from the specimens, which were cold-rolled and annealed at 500 , and the delamination plane was parallel to the rolling plane. In-situ composite weak interfaces effect has great impact on the fracture surface.

Cold-Rolling and Subsequent Annealing of Ti-Rich Tial Polysynthetically Twinned (PST) Crystals

1990 ◽  
Vol 213 ◽  
Author(s):  
M.H. Oh ◽  
H. Inui ◽  
S.R. Nishitani ◽  
M. Yamaguchi
Keyword(s):  
Dislocation Density ◽  
Cold Rolling ◽  
Shear Deformation ◽  
Lamellar Structure ◽  
Room Temperature ◽  
Subsequent Annealing ◽  
Second Stage ◽  
Cold Rolled ◽  
Two Stages ◽  
Equiaxed Grains

ABSTRACTPolysynthetically twinned (PST) crystals of Ti-rich TiAl have been grown and specimens cut from these crystals have been rolled at room temperature and subsequently annealed at 900°C and 1000°C. When the shear deformation parallel to the lamellar boundaries occurs during rolling, PST crystals of Ti-rich TiAl can be rolled to about 50% reduction in thickness at room temperature.The recovery in microhardness occurs in two stages; the first stage associated with the decrease in dislocation density and the second stage connected with the annealing-out of deformation induced twins. The recrystallization mode depends on the amount of reduction. Up to 20% reduction, the lamellar structure is preserved even after the full recovery in hardness. When the amount of reduction exceeds 40%, a structure composed of equiaxed grains of TiAl is obtained after recrystallization. A mechanism of recrystallization of cold-rolled PST crystals, which may explain the dependence of recrystallization mode on the amount of reduction, is proposed.

scholarly journals EBSD study of microstructure evolution of ferritic stainless steel during cold rolling and annealing

2018 ◽  
Vol 190 ◽  
pp. 11007
Author(s):  
Chi Zhang ◽  
Yijie Xu ◽  
Liwen Zhang ◽  
Yinlin Gu
Keyword(s):  
Cold Rolling ◽  
Microstructure Evolution ◽  
Shear Bands ◽  
Inhomogeneous Deformation ◽  
Rolled Sample ◽  
Ferritic Stainless Steels ◽  
High Deformation ◽  
Cold Rolling And Annealing ◽  
Cold Rolled ◽  
Ebsd Technique

The microstructure and texture of ferritic stainless steels (FSSs), formed during cold rolling and annealing processes, determine the mechanical properties of final sheet, especially the deep drawing formability. In this work, aNb, Ti stabilized17%Cr FSS was cold rolled with the reductions of 20%~70% and annealed for periods at 700°C. EBSD technique was used to characterize the microstructure evolution and inhomogeneous deformation strain distribution of the sheet during cold rolling. Partially annealed sheets were also analyzed to observe the nucleation and growth of recrystallized grains. Special attentions were paid on the crystal orientation of the deformed grains and recrystallzed grains. The results infer that in-grain shear band was formed in the cold rolled sample with the reduction higher than 30%, associated with the formation of high deformation strains. And the recrystallized grains prefer to form at some unique grain boundaries and in-grain shear bands. The orientations of recrystallized grains relates to the deformed grains.

scholarly journals The Effects of Annealing at Different Temperatures on Microstructure and Mechanical Properties of Cold-Rolled Al0.3CoCrFeNi High-Entropy Alloy

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 940
Author(s):  
Zichao Zhu ◽  
Tongtong Yang ◽  
Ruolan Shi ◽  
Xuantong Quan ◽  
Jinlong Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Annealing Temperature ◽  
Crystal Defects ◽  
High Entropy Alloy ◽  
Rolled Sample ◽  
High Entropy ◽  
Cold Rolling And Annealing ◽  
Cold Rolled ◽  
Strength And Toughness

In this work, cold-rolling was utilized to induce a high density of crystal defects in Al0.3CoCrFeNi high-entropy alloys. The effects of annealing temperature on static recrystallization, precipitation behavior and mechanical properties were investigated. With increasing annealing temperature from 590 °C to 800 °C, the area fraction of recrystallized region increases from 26.9% to 93.9%. Cold-rolling deformation largely promotes the precipitation of B2 phases during annealing, and the characteristics of the precipitates are linked to recrystallization level. The coarse and equiaxed B2 phases exist in the recrystallized region and the fine and elongated B2 phases occupy the non-recrystallized region. Combined use of cold-rolling and annealing can remarkably enhance the strength and toughness. A partially recrystallized microstructure in a cold-rolled sample annealed at 700 °C exhibits a better combination of strength and toughness than a fully recrystallized microstructure in a cold-rolled sample annealed at 800 °C. Finally, related mechanisms are discussed.

Effect of Aging Treatment on Mechanical Properties and Electrical Conductivity of Cu-5.7%Cr In Situ Composite Produced by Equal Channel Angular Pressing

2012 ◽  
Vol 560-561 ◽  
pp. 344-348 ◽  
Author(s):  
Wei Wei ◽  
Kun Xia Wei ◽  
Igor V. Alexandrov ◽  
Qing Bo Du ◽  
Jing Hu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Equal Channel Angular Pressing ◽  
Aging Treatment ◽  
In Situ Composite ◽  
Angular Pressing ◽  
Peak Aging ◽  
Average Size ◽  
Equiaxed Grains

The effect of aging treatment on mechanical properties and electrical conductivity of Cu-5.7%Cr in situ composite produced by equal channel angular pressing (ECAP) was investigated here. The rotation and spreading of Cr particles was observed in Cu-5.7%Cr alloy during the ECAP, resulting in long thin in situ filaments. The equiaxed grains of the Cu phase with an average size of 200 nm were developed after eight passes of ECAP. When aging at 400~450 °C for 1 h, Cu-5.7%Cr composite after ECAP shows the maximum microhardness, and the electrical conductivity is larger than 70% of IACS. At 400 °C, the peak aging time appears for 0.5~2 h, dependent on the pre-strain for all ECAP samples. With the increase of ECAP passes, the enhancement of tensile strength due to the aging treatment declines, and even shows negative after eight passes of ECAP. The combination of ECAP and aging treatment would be a promising process to balance mechanical properties and electrical conductivity of Cu-5.7%Cr composite.

scholarly journals Effect of cold rolling and annealing temperature to the characteristics of α + β' phases in Cu-29.5Zn-2.5Al alloy produced by gravity casting

2020 ◽  
Vol 56 (1) ◽  
pp. 89-97
Author(s):  
I. Angela ◽  
I. Basori ◽  
B.T. Sofyan
Keyword(s):  
Cold Rolling ◽  
Shear Bands ◽  
X Ray Diffraction ◽  
Gravity Casting ◽  
X Ray ◽  
Low Temperature Annealing ◽  
Slip Bands ◽  
Cold Rolling And Annealing ◽  
Higher Temperature ◽  
Cold Rolled

Al-brass alloys (Cu29.5Zn2.5Al wt. %) were produced by gravity casting and homogenized at 800?C for 2 h, resulting in a binary phase morphology identified as cubic ? and martensitic ?? phases through X-ray diffraction (XRD). Samples were then subsequently cold rolled and annealed at 150, 300, 400, and 600?C for 30 minutes. Visible traces of slip, intersecting slip bands, and shear bands were observed in microstructure images of the samples after each progressive deformation stage. Deformation-induced martensites were present after 20 % cold rolling. Higher thickness reduction resulted in simultaneous strain hardening of the phases. Low temperature annealing slightly increased microhardness, of both ? and ??, due to the formation of precipitates. SEM-EDX analysis showed that no solute segregation was found in annealed samples. Annealing at higher temperature resulted in conventional softening. Recrystallized equiaxed ?? phase grains were visible after annealing at 600?C.

On Preparation of In Situ Composite Steel with Ultra-High Strength and its Thermal Stability

2010 ◽  
Vol 152-153 ◽  
pp. 436-440
Author(s):  
Jun Zhao ◽  
Han Zhang ◽  
Zhi Wang ◽  
Hong Yan Zhai ◽  
Quan Xing Wen ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Crystal Size ◽  
Steel Plate ◽  
Lath Martensite ◽  
Rolling Direction ◽  
High Strength ◽  
Long Time ◽  
New Type ◽  
Lath Morphology

A new type of in-situ composite nano-multilayer plate with ultra-high strength (b 2112 MPa), Q235 steel plate with nano-layered structure of lath martensite produced by severe cold-rolling, was developed. After cold-rolling, subsequent annealing has great effect on the deformed lath morphology and grain refinement. Microstructure recrystallizing course have taken place after long time annealing at 350 °C. The recrystallization activation energy is 151 kJmol-1. Microstructure characteristics along rolling direction arrangement was decreased after annealing at 400 °C. In addition to the ultrafine ferrite grains, nano-carbides precipitated uniformly in the specimen annealed at 500 °C. Annealing at and above 600 °C resulted in coarse ferrite grains with spheroidized coarse carbides, causing grain growth. The average crystal size is about 4.7 m after annealing for 60 min at 600 °C.

Superplasticity in Nb3Al/Nb In Situ Composites

1999 ◽  
Vol 601 ◽  
Author(s):  
S. Hanada ◽  
W. Fang
Keyword(s):  
Superplastic Deformation ◽  
Grain Boundary Sliding ◽  
Al Alloy ◽  
Two Phase ◽  
Dislocation Glide ◽  
In Situ Composite ◽  
Al Content ◽  
Boundary Sliding ◽  
Equiaxed Grains

AbstractMicrostructures of a binary Nb-15.8at%Al alloy ingot were controlled by isothermal forging and heat treatment to produce equiaxed, fine grains of Nb3Al and Nb solid solution (Nb33). Nb3Al/Nb33 two phase alloy (in-situ composite) is found to exhibit superplasticity especially when one of the constituent phases, Nb33, is supersaturated. During superplastic deformation Nb33 transforms to Nb3Al, and Al content in Nb33 decreases. After superplastic deformation the microstructure consisting of equiaxed grains is left unchanged, although a slight grain growth is observed. It is suggested that stress induced by grain boundary sliding is effectively accommodated through dislocation glide and climb in the soft Nb33

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