Microhardness evolution of pure titanium deformed by equal channel angular extrusion

2019 ◽  
Vol 116 (4) ◽  
pp. 408 ◽  
Author(s):  
Shokouh Attarilar ◽  
Mohammad-Taghi Salehi ◽  
Faramarz Djavanroodi
Keyword(s):  
Vickers Microhardness ◽  
Equal Channel Angular Extrusion ◽  
Pure Titanium ◽  
Processing Temperature ◽  
Cross Sectional ◽  
Commercial Pure Titanium ◽  
Angular Extrusion ◽  
Suitable Amount ◽  
Sectional Plane ◽  
The One

Microhardness homogeneity was assessed on commercial pure titanium processed by equal channel angular extrusion (ECAE). The operation was performed with die channel angle of 90° and processing temperature of 450 °C by route BC up to six passes. The Vickers microhardness measurements were investigated on both cross-sectional and longitudinal planes of the annealed, one-, two-, four-, and six-pass ECAEed titanium. It was found that the application of the process and the addition of pass numbers lead to the improvement of hardness magnitude. It was shown that there are some areas of microhardness heterogeneity in surrounding and bottom regions of the one-pass and two-pass specimens at the cross-sectional plane which is slightly disappeared by adding the pass numbers. Furthermore, there is a suitable amount of hardness homogeneity in the longitudinal plane, irrespective of the specimen condition. It can be concluded that a desirable homogeneity of hardness can be attained after imposing six passes of ECAE process on both cross-sectional and longitudinal planes of titanium.

Texture evolution in commercially pure titanium after warm equal channel angular extrusion

2011 ◽  
Vol 59 (3) ◽  
pp. 1121-1133 ◽  
Author(s):  
Satyam Suwas ◽  
B. Beausir ◽  
L.S. Tóth ◽  
J.-J. Fundenberger ◽  
G. Gottstein
Keyword(s):  
Equal Channel Angular Extrusion ◽  
Texture Evolution ◽  
Pure Titanium ◽  
Commercially Pure Titanium ◽  
Commercially Pure ◽  
Angular Extrusion

scholarly journals Multi-Scale Modeling of Texture Evolution in Beryllium and Zirconium during Equal Channel Angular Extrusion

2009 ◽  
Vol 633-634 ◽  
pp. 483-510 ◽  
Author(s):  
Irene J. Beyerlein ◽  
Laurent Capolungo ◽  
G.G. Yapici ◽  
Carlos N. Tomé ◽  
Ibrahim Karaman
Keyword(s):  
Basal Slip ◽  
Equal Channel Angular Extrusion ◽  
Texture Evolution ◽  
Prismatic Slip ◽  
Processing Route ◽  
Processing Temperature ◽  
Active Deformation ◽  
Multi Scale ◽  
Extrusion Processing ◽  
Angular Extrusion

This work studies the deformation mechanisms active in two pure hexagonal close packed metals, beryllium (Be) and zirconium (Zr), during equal channel angular extrusion processing. An experimental-theoretical approach is employed to assess their relative contributions through measurement and calculation of texture evolution. A new multi-scale constitutive model, incorporating thermally activated dislocation density based hardening, is shown to effectively predict texture evolution as a function of processing route, number of passes (up to four), initial texture, pressing rate, and processing temperature. Texture predictions are shown to be in very good agreement with experimental measurements. Also, it is found that the two most active deformation modes in Be are basal slip and prismatic slip, where the predominant one is interestingly found to depend on die angle. Deformation in Zr during the first pass is predicted to be accommodated not only by its easiest mode, prismatic slip, but by basal slip and tensile twinning.

Microstructure Evolution and Mechanical Properties of Mg Alloy AZ31D Processed by Equal Channel Angular Extrusion

2007 ◽  
Vol 551-552 ◽  
pp. 651-656
Author(s):  
Yan Shu Zhang ◽  
Zhi Peng Zeng ◽  
X.F. Liu ◽  
Quan Lin Jin
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Microstructure Evolution ◽  
Equal Channel Angular Extrusion ◽  
Processing Temperature ◽  
Maximum Elongation ◽  
High Angle ◽  
Angular Extrusion ◽  
Elongation To Failure

The microstructure evolution and mechanical properties of magnesium alloy AZ31D processed by equal channel angular extrusion(ECAE) are studied. The processing temperature and the passes of extrusion are important factors to affect the microstructure and mechanical properties of the magnesium alloy during ECAE. In this paper, ECAE was performed at the temperature from 523 to 673K. The ductility increased through the grain refinement after the ECAE because the recrystallization took place and high angle grain boundary formed. The elongation of magnesium alloys AZ31D was improved after the ECAE. The maximum elongation-to-failure of magnesium alloys AZ31D processed by ECAE for 4 passes at 573K and strain rate of 0.5 10−4 s−1 × was 350%.

scholarly journals Microhardness Characteristics of Al-6063 Alloy Processed by Equal Channel Angular Extrusion

2014 ◽  
Vol 564 ◽  
pp. 513-518 ◽  
Author(s):  
J. Nemati ◽  
Shamsuddin Sulaiman ◽  
B.T. Hang Tuah Baharudin ◽  
M.A. Azmah Hanim ◽  
G.H. Majzoobi
Keyword(s):  
Detailed Analysis ◽  
Vickers Microhardness ◽  
Equal Channel Angular Extrusion ◽  
Inner Surface ◽  
Microhardness Testing ◽  
Angular Extrusion ◽  
Ram Speed ◽  
Vickers Microhardness Testing ◽  
Grain Diameter

In this study, annealed AL-6063 alloy was processed by the Equal Channel Angular Extrusion (ECAE) up to 6 passes at a temperature of 200°c following route A with a constant ram speed of 30 mm/min through a die angle of 90° between the die channels. The influence of ECAE processing on the evolution of microhardness in the material was studied using Vickers microhardness testing. The detailed analysis was carried out on the samples of as-received, one, two, three, four, five, and six pass conditions. The grain diameter reduced from 45μm to 2.8 μm after 6 passes of ECAE. The results indicated around 90% increase in Microhardness after 5 passes. Hardness of the inner surface where the billet was under compression was slightly higher than that of the mid-surface.

Microstructure Evolution and Mechanical Properties of AZ 31 Mg Alloy Processed by Equal Channel Angular Extrusion

2005 ◽  
Vol 488-489 ◽  
pp. 601-604 ◽  
Author(s):  
Li Jin ◽  
Dong Liang Lin ◽  
Da Li Mao ◽  
Xiao Qing Zeng ◽  
Wen Jiang Ding
Keyword(s):  
Mechanical Properties ◽  
Yield Stress ◽  
Grain Refinement ◽  
Microstructure Evolution ◽  
Equal Channel Angular Extrusion ◽  
Large Angle ◽  
Az31 Alloy ◽  
Mg Alloy ◽  
Processing Temperature ◽  
Angular Extrusion

Microstructure evolution and mechanical properties of AZ31 Mg alloy during equal channel angular extrusion (ECAE) at the temperature range of 453-498K was investigated. The processing temperature is an important factor to affect the microstructure and mechanical properties of the Mg alloy during ECAE. ECAE processing can be practiced at 498k or upon the temperature for as-received AZ31 alloy. A new two-step ECAEed processing was successfully used with lowing the processing temperature to 453k. The ductility increased but yield stress decreased though the grain refinement after ECAE at 498k because the recrystallization took place and large angle grain boundary formed. However both the ductility and yield stress were increased after two-step ECAE, which was ascribed to grain refinement as well as incomplete dynamic recovery and recrystallization during the processing.

scholarly journals Combining Equal-Channel Angular Extrusion (ECAE) and Heat Treatment for Achieving High Strength and Moderate Ductility in an Al-Cu Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 685-690 ◽  
Author(s):  
Matthias Hockauf ◽  
Lothar W. Meyer ◽  
Lutz Krüger
Keyword(s):  
Heat Treatment ◽  
Equal Channel Angular Extrusion ◽  
Failure Strain ◽  
Solution Treatment ◽  
High Strength ◽  
Ultimate Tensile Stress ◽  
Processing Temperature ◽  
Strength Increase ◽  
High Temperature Short Time ◽  
Angular Extrusion

The effect of equal-channel angular extrusion (ECAE) on mechanical properties of an AA2017 produced by powder metallurgy is investigated. Special attention is given to the influence of heat treatment, processing temperature and backpressure on the workability for achieving high strength and moderate ductility. This is of special interest, since it is often reported that Al-Cu alloys have low ductility and therefore are prone to cracking during severe plastic deformation. It is shown that ECAE at high temperatures (>220°C) does not necessitate backpressure to ensure homogeneous deformation but leads to a significant sacrifice in strength due to in-situ precipitation. Thus, most of the extrusions are done at considerably low temperatures. Performing room temperature-extrusion is most effective in achieving high strengths but also requires high backpressures. Due to severe strain hardening during processing, the strength increase is combined with a reduction in ductility. Recently it was reported that a post-ECAE aging of pre-ECAE solution treated material is effective in enhancing the ductility of aluminium alloys. This approach was successfully transferred to the current alloy. A high-temperature, short-time aging after only one extrusion, for example, doubles the failure strain to a value of ~13%. Compared to the naturally aged condition with coarse grains that serves as reference (T4), an increase of 15 % in yield stress (YS) was obtained while retaining the ultimate tensile stress (UTS). Another effective approach is the combination of a pre-ECAE solution treatment with subsequent under-aging prior to ECAE. It is shown that performing ECAE at medium temperatures (160-180°C) enables a better workability and additionally gives higher strengths and better ductility compared to the processing in the water quenched condition. A remarkable YS of 530 MPa and an UTS of 580 MPa combined with a moderate failure strain of 11.6 % were achieved.

Internalizing Behavior During the Transition from Childhood to Adolescence

2010 ◽  
Vol 26 (3) ◽  
pp. 187-193 ◽  
Author(s):  
Marc Vierhaus ◽  
Arnold Lohaus ◽  
Indra Shah
Keyword(s):  
Research Design ◽  
Internalizing Symptoms ◽  
Fourth Graders ◽  
Cross Sectional Study ◽  
Second Graders ◽  
Internalizing Behavior ◽  
Longitudinal Assessment ◽  
Sectional Study ◽  
Cross Sectional ◽  
The One

This investigation focuses on the question whether assessments of the development of internalizing behavior from childhood to adolescence are affected by the kind of research design (longitudinal versus cross-sectional). Two longitudinal samples of 432 second-graders and 366 fourth graders participated in a longitudinal study with subsequent measurements taken 1, 2, and 3 years later. A third sample consisting of 849 children covering the same range of grades participated in a cross-sectional study. The results show that the development of internalizing symptoms in girls – but not in boys – varies systematically with the research design. In girls, there is a decrease of internalizing symptoms (especially between the first two timepoints) in the longitudinal assessment, which may reflect, for example, the influence of strain during the first testing situation. Both longitudinal trajectories converge to a common trajectory from grade 2 to grade 7 when controlling for this “novelty-distress effect.” Moreover, when we control this effect, the slight but significant decrease characterizing the common trajectory becomes similar to the one obtained in the cross-sectional study. Therefore, trajectories based on longitudinal assessments may suggest more changes with regard to internalizing symptoms over time than actually take place, while trajectories based on cross-sectional data may be characterized by an increased level of internalizing symptoms. Theoretical and practical implications of these results are discussed.

Effect of Varied Probe Length on the Resonant Frequency of a Circular Cross-Sectional Cavity

2005 ◽  
Vol 2 (2) ◽  
pp. 79
Author(s):  
Mohd Khairul Mohd Salleh ◽  
Mohamad Syukri Suhaili ◽  
Zuhani Ismail ◽  
Zaiki Awang
Keyword(s):  
Resonant Frequency ◽  
Cavity Resonator ◽  
Simple Design ◽  
Cross Sectional ◽  
Probe Length ◽  
Mode Wave ◽  
The One

A simple design of a metallic circular cross-sectional air-filled cavity is presented. Two probes of varied lengths are used to excite TE112-mode wave into the cavity to give a resonant frequency of 5.86 GHz. The experiments show that the resonant frequency of the cavity resonator decreases as the lengths of the probes are increased. The shortest probe in the range of study gives the closest resonant frequency to the one desired.

Failure Analysis Due to Slightly Unetched Hard Mask Using Nano Probe

2013 ◽  
Author(s):  
Jong Hak Lee ◽  
Jong Eun Kim ◽  
Chang Su Park ◽  
Nam Il Kim ◽  
Jang Won Moon ◽  
...  
Keyword(s):  
Leakage Current ◽  
Circuit Simulation ◽  
The State ◽  
Physical Analysis ◽  
Cross Sectional ◽  
Hard Mask ◽  
Current Flows ◽  
Voltage Contrast ◽  
The One ◽  
Zero Voltage

Abstract In this work, a slightly unetched gate hard mask failure was analyzed by nano probing. Although unetched hard mask failures are commonly detected from the cross sectional view with FIB or FIB-TEM and planar view with the voltage contrast, in this case of the very slightly unetched hard mask, it was difficult to find the defects within the failed area by physical analysis methods. FIB is useful due to its function of milling and checking from the one region to another region within the suspected area, but the defect, located under contact was very tiny. So, it could not be detected in the tilted-view of the FIB. However, the state of the failure could be understood from the electrical analysis using a nano probe due to its ability to probe contact nodes across the fail area. Among the transistors in the fail area, one transistor’s characteristics showed higher leakage current and lower ON current than expected. After physical analysis, slightly remained hard mask was detected by TEM. Chemical processing was followed to determine the gate electrode (WSi2) connection to tungsten contact. It was also proven that when gate is floated, more leakage current flows compared to the state that the zero voltage is applied to the gate. This was not verified by circuit simulation due to the floating nodes.

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