Hot tensile characterization of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy with an equiaxed microstructure
TL;DR: In this paper, hot tensile tests were performed on Ti-6.5Al-3.3Si alloy with an equiaxed microstructure in the temperature range of 900-980°C with a constant strain rate of 0.001 s −1.
About: This article is published in Materials & Design.The article was published on 2009-03-01. It has received 12 citations till now. The article focuses on the topics: Grain Boundary Sliding & Equiaxed crystals.
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TL;DR: By integrating the thermomechanically coupled simulation with the mathematically modeling of microstructure evolution using Finite Element Method (FEM), the study of the dynamic recrystallization (DRX) of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy in β-forging process is conducted as mentioned in this paper.
57 citations
25 Jun 2011-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the deformation behavior of AZ31 Mg alloy has been studied in relation to test temperature and grain size, and the double twin mode was observed especially in large grained specimens at low homologous temperatures.
Abstract: Deformation behavior of AZ31 Mg alloy has been studied in relation to test temperature and grain size. Tensile specimens were prepared in the rolling direction of an as-rolled as well as a strip-cast sheet with 1 mm thickness. The as-rolled and strip-cast sheets had the mean grain sizes of 75 μm and 5 μm, respectively. Tensile tests were then carried out under the strain rate of 10 −2 /s at room temperature, 100 °C, and 200 °C. Biaxial tests were also performed to obtain flow curves in terms of stress and strain as well as to estimate the biaxial forming limit. Plastic deformation was found due to the usual dislocation slip and dynamic recrystallization (DRX) together with some twinning. A number of twins were observed especially in large grained specimens at low homologous temperatures. The strip-cast sheet exhibited many small grains generated by the DRX at higher temperature. These fine grains due to DRX appeared to lead into an enhanced formability, evidenced by a sudden formability increase of a strip-cast sheet at 200 °C. The double twin mode was observed under biaxial loading, contrary to extension twins observed under uniaxial loading.
37 citations
TL;DR: In this article, the effects of Al content (2.2 and 6.9 ) on structure and mechanical properties of the hot-rolled ZrTiAlV alloy samples were investigated.
31 citations
TL;DR: In this article, the authors investigated the effect of electroshocking treatment on the microstructure and mechanical properties of titanium alloys and found that the energy introduced by EST resulted in changes to the direction and intensity of texture within the micro-structure with the texture intensity of the α phase increasing from 4.94 to 8.52 and that of β both increased from 3.35 to 9.88 after 0.04 s EST.
Abstract: Electro-shocking treatment (EST) has been investigated as a pathway to optimise the microstructure and mechanical properties of titanium alloys. The thermal conditions introduced by EST resulted in a phase transformation from α to β. The fraction of β phase decreased from 25.27% to 19.47% after EST for 0.02 s, which was possibly caused by the recrystallization of α phase. The application of EST for 0.04 s resulted in an increase in volume fraction of the β phase to 26.95%. The energy introduced by EST resulted in changes to the direction and intensity of texture within the microstructure with the texture intensity of the α phase increasing from 4.94 to 8.52, and that of β both increased from 3.35 to 9.88 after 0.04 s EST.
27 citations
TL;DR: In this paper, a set of self-fabricated ultrasonic burnishing equipment was used to strengthen the surface of TC11 titanium alloy material by using a roller tip with or without heat treatment.
Abstract: A roller tip was utilized in a set of self-fabricated ultrasonic burnishing equipment. Ultrasonic roller burnishing with/without heat treatment was proposed and investigated in the surface strengthening of TC11 titanium alloy material. Experimental research together with finite element analysis were carried out to perform the study. Three treatments, including conventional turning, ultrasonic roller burnishing at ambient temperature (URB) and ultrasonic roller burnishing at medium temperature (URB/HT), were comparatively evaluated in term of surface integrity and corrosion resistance of the treated sample. As a result, compared with URB, the surface of TC11 alloy treated by URB/HT had better surface finishing, which significantly improved corrosion resistance, and thus the surface of TC11 alloy was strengthened. The good performance of URB/HT was attributed to the combined effect of the high frequency dynamic impact from URB and the thermoplastic effect of the heat treatment. Owing to the excitation of the ultrasonic vibration during URB, an oscillating stress wave formed and propagated deep inside the being treated material, and the heat treatment in URB/HT case was supposed to accelerate this sort of stress propagation. Meanwhile, both the heat treatment and the dynamic oscillating stress wave facilitated the deformation of the surface layer.
23 citations
References
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31 Jan 2002-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the superplastic behavior of the ultrafine-grained (UFG) Ti-6A1-4V alloy produced by high pressure torsion (HPT) has been studied.
Abstract: Superplastic behavior of the ultrafine-grained (UFG) Ti–6A1–4V alloy produced by high pressure torsion (HPT) has been studied. High elongations (more than 500%) have been observed in this alloy during tensile tests at relatively low temperatures and high strain rates. At the same time, the superplastic behavior of this alloy has several specific features such as the relatively low values of strain rate sensitivity of flow stress and significant strain hardening. Moreover, it was shown that the alloy, processed by HPT, demonstrates an outstanding room temperature strength about 1500 MPa after superplastic deformation.
127 citations
"Hot tensile characterization of Ti–..." refers background in this paper
...After hot deformation at 920 C and 940 C, equiaxed microstructure was kept and the grain size was slightly increased, which are the typical microstructure characteristics of superplastic deformation [12,13]....
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...5), which is caused by local necking [12]....
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...Then stable flow with low stress in the temperature range of 920–980 C was observed, which is a typical characteristic of superplastic deformation [12]....
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TL;DR: In this article, a modified Norton-Hoff law is proposed to characterize the tensile behaviour of a superplastic titanium alloy and the results of these tests, supplemented with microstructural investigations, allow, as a function of temperature and strain rate, the determination of mechanical properties such as flow stress, strain hardening and fracture strain.
75 citations
TL;DR: In this paper, superplasticity was obtained from electrodeposited nanocrystalline nickel at 350°C, which is 0.36 of the melting point T m. A maximum elongation of 895% was obtained at 0.4 T m, which is a large reduction in temperature and increase in elongation over the previously reported best result for nickel.
57 citations
TL;DR: In this paper, a novel approach to the fabrication of a globularized fine-grained structure in γ+α2 titanium aluminide alloys has been proposed, which includes the use of specially designed alloys and a Globularization Anneal that excludes any primary hot working.
48 citations
"Hot tensile characterization of Ti–..." refers background in this paper
...The onset of flow softening might indicate the initiation of dynamic recrystallization [15]....
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20 Aug 2008-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the effects of hot compression and heat treatment on the microstructure and tensile property of Ti-6.5Al, 3.5Mo, 1.5Zr, and 0.3Si alloy with a widmanstatten micro-structure were investigated.
Abstract: The present work investigated the effects of hot compression and heat treatment on the microstructure and tensile property of Ti–6.5Al–3.5Mo–1.5Zr–0.3Si alloy with a widmanstatten microstructure. During hot compression at 995 °C, the lamellar α phase in the widmanstatten structure was distorted, and an equiaxed microstructure was obtained by subsequent duplex annealing of the hot-compressed sample. The tensile strength and elongation were significantly improved by hot compressing at 995 °C. Duplex annealing treatment resulted in a further increase in ductility at the expense of slight decrease in strength. A good combination of tensile strength (990 MPa) and elongation (12.8%) has been obtained by hot compression at 995 °C followed by the duplex annealing treatment.
47 citations
"Hot tensile characterization of Ti–..." refers methods in this paper
...3Si alloy with equiaxed grains of about 9 lm, which was obtained by the previous investigation [11]....
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