scholarly journals Microstructural and ageing response assessment of eutectic Al-Cu alloy due to isothermal heat treatment in semisolid state

2020 ◽  
Vol 7 (1) ◽  
pp. 016518
Author(s):  
Abhimanyu Chaudhari ◽  
Purnendu Nasker ◽  
Ankur Srivastava ◽  
Sudeep Paul ◽  
Ajit Kumar Chakrabarti
Keyword(s):  
Heat Treatment ◽  
Response Assessment ◽  
Isothermal Heat Treatment ◽  
Semisolid State ◽  
Cu Alloy

Single-layer submicron-thick BaTiO3 coatings from poly(vinylpyrrolidone)-containing sols: Gel-to-ceramic film conversion, densification, and dielectric properties

2001 ◽  
Vol 16 (11) ◽  
pp. 3116-3123 ◽  
Author(s):  
Hiromitsu Kozuka ◽  
Atsushi Higuchi
Keyword(s):  
Heat Treatment ◽  
Condensation Reaction ◽  
Single Layer ◽  
Dip Coating ◽  
Single Step ◽  
Dielectric Constants ◽  
Isothermal Heat Treatment ◽  
Coating Films ◽  
Ceramic Film ◽  
C Decomposition

BaTiO3-coating films were prepared from a solution containing poly(vinylpyrrolidone) (PVP) of molar composition Ba(CH3COO)2:Ti(OC2H5)4:PVP:CH3COOH:H2O: C2H5OH = 1:1:0.5:27:4:5, via nonrepetitive, single-step dip-coating. The gel films were found to be converted into BaTiO3 films via evaporation of the solvent and CH3COOH below 210 °C, decomposition of PVP at 210–360 °C, decomposition of CH3COO− below 440 °C, and crystallization at 500–610 °C. The decomposition of PVP was accompanied by the progress of the condensation reaction, which resulted in significant reduction in film thickness. When the gel films were heated isothermally at 700 °C, crack-free BaTiO3 films as thick as 0.9 μm were obtained. When the gel films were heated isothermally at 360 °C and then at 700 °C, the film became denser. Higher dielectric constants around 290 were found for the film that underwent the isothermal heat treatment at 360 °C. A slower rate of PVP decomposition was thought to be the key for the film densification.

Study on Over-Burnt Temperature and Heat Treatment of a New Al-Mg-Si-Cu Alloy

2011 ◽  
Vol 284-286 ◽  
pp. 1516-1519
Author(s):  
Yi Meng ◽  
Zhi Hao Zhao ◽  
Jian Zhong Cui
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Homogenization Temperature ◽  
Microstructure Analysis ◽  
Cu Alloy ◽  
Homogenization Time ◽  
The Way

The over-burnt temperature of a new Al-Mg-Si-Cu Aluminum alloy was studied by means of DSC and microstructure analysis, as a result of the homogenization temperature being obtained. A favorable homogenization time was got by the way of the dependence of area fractions of remnant phases on homogenization time being calculated. According to experimentation results, the over-burnt temperature of the new Al-Mg-Si-Cu Aluminum alloy was 570°C, and the way to homogenize the new alloy at 560°C for 24h was excellemt.

scholarly journals Influence of Microstructure on Mechanical Properties of Bainitic Steels in Railway Applications

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 778 ◽  
Author(s):  
Omid Hajizad ◽  
Ankit Kumar ◽  
Zili Li ◽  
Roumen H. Petrov ◽  
Jilt Sietsma ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Mechanical Behavior ◽  
Mechanical Performance ◽  
Electron Backscatter Diffraction ◽  
Bainitic Ferrite ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Uniaxial Tensile ◽  
Isothermal Heat Treatment

Wheel–rail contact creates high stresses in both rails and wheels, which can lead to different damage, such as plastic deformation, wear and rolling contact fatigue (RCF). It is important to use high-quality steels that are resistant to these damages. Mechanical properties and failure of steels are determined by various microstructural features, such as grain size, phase fraction, as well as spatial distribution and morphology of these phases in the microstructure. To quantify the mechanical behavior of bainitic rail steels, uniaxial tensile experiments and hardness measurements were performed. In order to characterize the influence of microstructure on the mechanical behavior, various microscopy techniques, such as light optical microscopy (LOM), scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), were used. Three bainitic grades industrially known as B360, B1400 plus and Cr-Bainitic together with commonly used R350HT pearlitic grade were studied. Influence of isothermal bainitic heat treatment on the microstructure and mechanical properties of the bainitic grades was investigated and compared with B360, B1400 plus, Cr-Bainitic and R350HT in as-received (AR) condition from the industry. The results show that the carbide-free bainitic steel (B360) after an isothermal heat treatment offers the best mechanical performance among these steels due to a very fine, carbide-free bainitic microstructure consisting of bainitic ferrite and retained austenite laths.

scholarly journals On the Development of an Al4.8 wt% Cu Alloy Obtained from Recycled Aluminum Cans Designed for Thixoforming Process

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Ronan Miller Vieira ◽  
Gianni Ferreira Alves Moreira ◽  
André Itman Filho ◽  
Estéfano Aparecido Vieira
Keyword(s):  
Solution Heat Treatment ◽  
Natural Aging ◽  
Tensile Tests ◽  
Permanent Mold ◽  
Semisolid State ◽  
Globular Microstructure ◽  
Cu Alloy ◽  
Heat Treated ◽  
Aluminum Cans ◽  
Melting And Solidification

This work has focused on the development of a new aluminum alloy containing 4.8 wt% of Cu alloy obtained from recycled aluminium cans designed for thixoforming process. After the step of melting and solidification of the alloy in a metallic permanent mold, samples were solution heat treated at 525°C for times ranging from 2 h to 48 h, quenched in water and followed by natural aging. Results have shown the evolution of hardness so from them solubilization solution heat treatment was chosen for 24 h. The best condition for aging was 190°C during 3 h. With this data pieces were thixoforged at 580°C and 615°C corresponding, respectively, to solid fraction (fs) of 0.8 and 0.6. The optimized T6 temper was applied and tensile tests were performed. The mechanical properties obtained are compatible with those obtained for consolidated alloys processed in semisolid state (SS) and after T6 temper hardness increases from 95 HB to 122 HB and the best results were a tensile strength of 324 MPa ± 10 MPa, yield strength of 257 MPa ± 18 MPa, and an elongation of 7.1%  ±  1%. For alloys designed for thixoforming process, these results are in accordance with what was expected whereas globular microstructure, high ductility, and good performance under cyclic conditions are desirable.

scholarly journals Significantly fast spinodal decomposition and inhomogeneous nanoscale martensitic transformation in Ti–Nb–O alloys

2020 ◽  
Vol 321 ◽  
pp. 11049
Author(s):  
Yuya ISHIGURO ◽  
Yuhki TSUKADA ◽  
Toshiyuki KOYAMA
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Spinodal Decomposition ◽  
Treatment Temperature ◽  
Phase Field Method ◽  
Isothermal Heat Treatment ◽  
Phase Decomposition ◽  
Rate Condition ◽  
Continuous Cooling ◽  
Β Phase

The β phase spinodal decomposition during continuous cooling in Ti‒Nb‒O alloys is investigated by the phase-field method. Addition of only a few at.%O to Ti‒23Nb (at.%) alloy remarkably increases the driving force of the β phase spinodal decomposition. During isothermal heat treatment at 1000 K and 1100 K in Ti‒23Nb‒3O (at.%) alloy, the β phase separates into β1 phase denoted as (Ti)1(O, Va)3 and β2 phase denoted as (Ti, Nb)1(Va)3, resulting in the formation of nanoscale concentration modulation. The phase decomposition progresses in 0.3‒20 ms. In Ti‒23Nb‒XO alloys (X = 1.0, 1.2, 2.0), the spinodal decomposition occurs during continuous cooling with the rate of 500 K s‒1, indicating that the spinodal decomposition occurs during water quenching in the alloys. It is assumed that there is a threshold value of oxygen composition for inducing the spinodal decomposition because it does not occur during continuous cooling in Ti‒23Nb‒0.6O (at.%) alloy. The concentration modulation introduced by the β phase decomposition has significant effect on the β→α” martensitic transformation. Hence, it seems that for controlling microstructure and mechanical properties of Ti‒Nb‒O alloys, careful control of heat treatment temperature and cooling rate condition is required.

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