High temperature microstructural evolution of 304L stainless steel as function of pre-strain and strain rate

Lee, Woei Shyan; Lin, Chi Feng; Chen, Tao Hsing; Yang, Meng

doi:10.1016/j.msea.2010.02.007

Cited by 45 publications

(13 citation statements)

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“…In 9 wt. % Ni -18 Cr austenitic stainless steel deformed in the temperature range of 300 -800 °C in the strain rate range of 2000 -6000 s -1 up to 50 % strain no twin formation was observed; the dislocation cell structure developed by 15 % strain; with an increase in temperature and a decrease in strain rate the dislocation density decreased and the cell size increased [26]. In 15.8 wt.…”

Section: Introductionmentioning

confidence: 94%

High temperature dislocation structure and NbC precipitation in three Ni–Fe–Nb–C model alloys

2015

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, O. O. (2015). High temperature dislocation structure and NbC precipitation in three NiFe-Nb-C model alloys. Journal of Materials Science, 50 (21), 7115-7125. High temperature dislocation structure and NbC precipitation in three NiFe-Nb-C model alloys AbstractIn this original work, the dislocation structure and NbC precipitation were investigated in three Ni-based alloys (70Ni-Fe-0.331Nb-0.040C, 70Ni-Fe-0.851Nb-0.114C and 70Ni-Fe-1.420Nb-0.157C, wt%) thermomechanically processed in the temperature range of 1250-1075 °C. The dislocation structure inhomogeneity (dislocation networks and cell walls), which we observed in the middle and high Nb+C alloys, resulted from the dislocation pile-ups in the vicinity of >200 nm NbC particles. The dislocation density around >200 nm particles exceeded the average values by 5-7 times, and that in the cell walls might exceed the average values by 10 times. Twins and stacking faults were observed in all alloys after solution treatment at 1250 °C, however, they were not observed after 1.2 strain at 1075 °C. The dislocation generation rate during deformation at 1075 °C varied with alloy composition and increased with an increase in the°C, the majority of particles were growing in the high Nb+C alloy, theNb+C alloy and all the particles were dissolving in the low Nb+C alloy. Deformation to 1.2 strain at 1075 °C resulted in strain-induced precipitation in all alloys andNb+C alloys. Twins and stacking faults were observed in all alloys after solution treatment at 1250 C, however they were not observed after 1.2 strain at 1075 C. The dislocation generation rate during deformation at 1075 C varied with alloy composition and increased with an increase in the < 20 nm particle number density. During cooling in the temperature range of 1250 -1075 C the majority of particles were growing in the high Nb+C alloy, the < 20 nm particles were growing in the middle Nb+C alloy, and all the particles were dissolving in the low Nb+C alloy.Deformation to 1.2 strain at 1075 C resulted in strain-induced precipitation in all alloys and < 20 nm particle growth in the high and middle Nb+C alloys.

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Section: Introductionmentioning

confidence: 94%

High temperature dislocation structure and NbC precipitation in three Ni–Fe–Nb–C model alloys

2015

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Section: Constitutive Models For Titanium Alloysmentioning

confidence: 96%

“…For TRIP steels: The results of experiment conducted by Russel et al [116] on the Fe85Cr4Mo8V2C1 alloy indicate that although high strain rates can promote the formation of martensite at the onset of deformation, the accompanying adiabatic heating will decrease the transformation rate with further straining. Lee et al [167] summarized the results of several dynamic experiments on steels where a contradiction aroused about the effects of strain rate on the martensitic transformations. Impact process can induce SIM transformation in deformed specimens, but the increment in strain rate and temperature will reduce the volume fraction of martensite.…”

Section: Constitutive Models For Titanium Alloysmentioning

confidence: 99%

“…It is generally recognized that the density of dislocations and mechanical twins will increase with increasing strain rate but decreasing temperature [110,118,120,167,168]. In addition, the morphology and distribution of dislocations and mechanical twins are also strain-rate and temperature dependent.…”

Section: Constitutive Models For Titanium Alloysmentioning

confidence: 99%

“…In addition, the morphology and distribution of dislocations and mechanical twins are also strain-rate and temperature dependent. Lee et al [118,120,169] concluded that with increasing strain rate the size of dislocation cells is reduced but the cell walls become thicker, while elevated temperatures will contribute to larger dislocation cells and thinner cell walls, as shown in Fig.18.According to Dudamell et al [170], thermal activation is critical for dislocation rearrangement. This explains that why high strain rates have adverse influence on the dislocation rearrangement and retard dynamic recovery.…”

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confidence: 99%

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The dynamic response of β titanium alloys to high strain rates at room and elevated temperatures

Zhan¹

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Titanium and its alloys fulfil a wide range of applications involving aerospace, biomedical, chemical and petroleum industries due to their extraordinary properties such as high specific strength, excellent biocompatibility and corrosion resistance. Among different types of titanium alloys, β titanium alloys have a unique range of properties such as an excellent combination of high strength and fracture toughness and low Young's modulus. Therefore, the usage of β titanium alloys in the manufacturing of some key components in aerospace and biomedical industries has continually increased in the past decade.Nowadays many commercial manufacturing processes for metallic materials such as machining, explosive welding, hot forging and extrusion employ high strain rates and are conducted at elevated temperatures. Also, high-strain-rate deformation can be encountered in collisions such as in car crashes, bird strikes on airplanes and micrometeorite impacts on space structures. Hence a large number of studies have been conducted on the dynamic response of metallic materials including copper, steels, tantalum, Ti-6Al-4V alloy and commercially pure titanium to high strain rates. Due to limited knowledge of the dynamic behaviour of β titanium alloys, this thesis mainly investigates the stress-strain behaviour and microstructural evolution of β titanium alloys under high strain rates at room and elevated temperatures.Split Hopkinson Pressure Bar compressive tests were carried out on two new types of β titanium alloys with different levels of β phase stability, the Ti-6Cr-5Mo-5V-4Al (wt. %) and Ti-25Nb-3Zr-3Mo-2Sn (wt.%) alloys, at strain rates ranging from 10 -3 s -1 to 10 4 s -1 and temperatures ranging from 293K to 1173K. The Ti-6Cr-5Mo-5V-4Al alloy, with relatively high β phase stability, represents an alloy type which can be engineered through heat treatment or thermo-mechanical processing to achieve a superior combination of strength and fracture toughness. While the Ti-25Nb-3Zr-3Mo-2Sn alloy with relatively low β phase stability represents an alloy type which can be applied in biomedical applications due to their low Young's modulus and superelastic properties.For the Ti-6Cr-5Mo-5V-4Al alloy, dislocation slip is dominant at all testing strain rates and temperatures in this research. The flow stress increases with increasing strain rate but decreasing temperature. Also, it is more sensitive to temperature than strain rate. At ambient temperatures, the strain hardening rate exhibited by the Ti-6Cr-5Mo-5V-4Al alloy at high strain rates is much lower than that at quasi-static strain rates, which is attributed to the thermal softening effect brought byHongyi Zhan II The University of Queensland adiabatic heating. While for the Ti-25Nb-3Zr-3Mo-2Sn alloy, multiple deformation mechanisms including dislocation slip, {332} <113> and {112} <111> mechanical twinning, stress-induced martensitic α" and ω phase transformations can be activated simultaneously and among them {332} <113> twinning is dominant at 293K regardless of...

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Strength and Ductility of Ultrafine Grained 304SS Prepared by Accumulative Rolling and Annealing

Xue

Shen

Liu

et al. 2013

Characterization of Minerals, Metals, and Materials 2013

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High temperature microstructural evolution of 304L stainless steel as function of pre-strain and strain rate

Cited by 45 publications

References 35 publications

High temperature dislocation structure and NbC precipitation in three Ni–Fe–Nb–C model alloys

High temperature dislocation structure and NbC precipitation in three Ni–Fe–Nb–C model alloys

The dynamic response of β titanium alloys to high strain rates at room and elevated temperatures

Strength and Ductility of Ultrafine Grained 304SS Prepared by Accumulative Rolling and Annealing

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