scholarly journals Differential Scanning Calorimetry Fingerprints of Various Heat-Treatment Tempers of Different Aluminum Alloys

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 763
Author(s):  
Zhixing Chen ◽  
Kun Liu ◽  
Emad Elgallad ◽  
Francis Breton ◽  
X.-Grant Chen
Keyword(s):  
Electrical Conductivity ◽  
Differential Scanning Calorimetry ◽  
Aluminum Alloys ◽  
Effective Means ◽  
Heat Treatments ◽  
Scanning Calorimetry ◽  
Structural Applications ◽  
Thermal Histories ◽  
Various Tempers ◽  
Dsc Curves

Heat-treatable cast and wrought aluminum alloys are widely used for structural applications in the automobile and aerospace industries. To assess and diagnose the production and quality problems related to industrial heat treatments, differential scanning calorimetry (DSC) was used as a tool in the present work to determine the thermal histories of samples that had undergone different tempers of three commonly used aluminum alloys, namely a high-pressure die-cast AlSi10Mg0.3Mn alloy, permanent-mold cast Al-Si-Cu 319 alloy, and extruded Al-Mg-Si AA6082 alloy. Various peaks detected in the DSC curves were analyzed and characterized to identify the precipitation/dissolution reactions of metastable phases, aiming to establish a “fingerprint” of each temper of the three experimental alloys. Results showed that both the number and size of exothermic peaks varied with the temper owing to distinct precipitation behaviors, providing an effective means of fingerprinting the various tempers. Meanwhile, electrical conductivity and microhardness data provided the supplementary support for the fingerprinting. The thermal histories of three experimentally heat-treated alloys were well traced and distinguished by the combination of DSC characteristics and electrical conductivity and microhardness results, promoting the DSC application in the quality control and verification of industrial heat treatments. In addition, the microstructures after the various tempers were observed to confirm the evolution of the precipitation reactions revealed in the DSC curves.

Thermal Analysis of Aluminum Alloys

2019 ◽  
Author(s):  
Daniel Larouche
Keyword(s):  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Quality Control ◽  
Aluminum Alloys ◽  
Isothermal Calorimetry ◽  
Curve Analysis ◽  
Cooling Curve ◽  
Scanning Calorimetry ◽  
Cooling Curve Analysis ◽  
Scientists And Engineers

Thermal analysis is applied on aluminum alloys by researchers to investigate mainly phase transformations, while it is regularly used for quality control purposes in industry. Techniques like cooling curve analysis, differential thermal analysis, differential scanning calorimetry, and isothermal calorimetry are amongst those most frequently used by scientists and engineers. These techniques will be described, and a mathematical description of the results will be developed. State-of-the-art quantification methods applied on aluminum alloys will be presented and criticized based on specific examples taken from the literature.

scholarly journals Development of Pressure-Responsive PolyPropylene and Biochar-Based Materials

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 339 ◽  
Author(s):  
Amir Noori ◽  
Mattia Bartoli ◽  
Alberto Frache ◽  
Erik Piatti ◽  
Mauro Giorcelli ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Electrical Conductivity ◽  
Differential Scanning Calorimetry ◽  
Plastic Deformation ◽  
Electrical Properties ◽  
Tea Leaves ◽  
Scanning Calorimetry ◽  
A Value ◽  
Wide Range ◽  
Order Of Magnitude

In this research paper, we reported the synthesis of biochar-based composites using biochar derived from exhausted tea leaves and polypropylene. The resulting materials were deeply characterized investigating mechanical (dynamic mechanical thermal analysis), thermal (thermogravimetrical analysis and differential scanning calorimetry), morphological (field emission scanning microscopy) and electrical properties vs. temperature. Furthermore, electrical conductivity was studied for a wide range of pressures showing an irreversible plastic deformation. An increment of one order of magnitude in the conductivity was observed in the case of 40 wt% biochar loading, reaching a value of 0.2 S/m. The material produced exhibited the properties of an irreversible pressure sensor.

Preparation of Two Novel Ionic Electroconductive Polyurethanes Functionalized with the Backbone of Ionic Liquid

2013 ◽  
Vol 668 ◽  
pp. 259-262
Author(s):  
Ding Jun Zhang ◽  
Chao Yun Qu ◽  
Yu Xian Chen
Keyword(s):  
Electrical Conductivity ◽  
Differential Scanning Calorimetry ◽  
Ionic Liquid ◽  
Surface Resistance ◽  
High Yield ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Facile Synthesis ◽  
Scanning Calorimetry ◽  
Structures And Properties

The facile synthesis of two new Ionic electroconductive polyurethanes with the framework of ionic liquids, i.e., PUR-T: synthesized with isocyanate TDI; PUR-H: synthesized with isocyanate HDL, are described. Their structures and properties were characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), Differential scanning calorimetry (DSC) and the surface resistance meter. The effects of the different kinds of isocyanate on electrical conductivity of PUR were also investigated. It was found that their electrical conductivity can be optimized by changing the reaction temperature. The PUR-H, which exhibits an electrical conductivity of 1.0×104 Ω surface resistance, could be obtained in high yield, up to 65% at 90 oC for 12h.

1H nuclear magnetic resonance, differential scanning calorimetry, and electrical conductivity studies on the phase transitions of pentylammonium chloride and the cationic self-diffusion in its rotator phase

1988 ◽  
Vol 66 (8) ◽  
pp. 1961-1969 ◽  
Author(s):  
Shigehiko Iwai ◽  
Ryuichi Ikeda ◽  
Daiyu Nakamura
Keyword(s):  
Phase Transition ◽  
Electrical Conductivity ◽  
Differential Scanning Calorimetry ◽  
Room Temperature ◽  
Stable Phase ◽  
Scanning Calorimetry ◽  
Nmr Studies ◽  
Self Diffusion ◽  
H Nmr ◽  
Rotator Phase

Measurements of 1H nmr, differential thermal analysis, and differential scanning calorimetry have revealed that solid pentylammonium chloride, cooled rapidly from room temperature, forms a mixture of the stable and metastable low-temperature phases below the phase transition temperature, Ttr (238 K). The sample annealed just below Ttr for 3 h was shown to consist of a single stable phase down to about 100 K, indicating the existence of a time-consuming phase transition taking place successively just below the normal transition. In the rotator phase obtainable above Ttr (257 K), 1H nmr studies proved the presence of axial rotation of the whole cation about the long axis, similar to n-paraffins in their rotator phase. Above room temperature, the onset of the translational self-diffusion of the cations within 2D planes in the layer structure of the rotator phase was detected by measuring the temperature dependence of electrical conductivity as well as 1H T1 and T1p. 2D self-diffusion constants and diffusional correlation times evaluated from the electrical conductivity observed between room and the melting temperatures indicate that the 2D cationic diffusion near the melting point is as fast as 3D self-diffusion in usual plastic crystals. Cationic motions in the two different rotator phases α and α′ are compared.

Comparison and Thermodynamic Analysis of Crystallinity of Noncrosslinking and Crosslinking Fluorinated Acrylate Copolymers Films

2011 ◽  
Vol 239-242 ◽  
pp. 1391-1395
Author(s):  
Hui Qin Chen ◽  
Bing Wu ◽  
Zhi Qi Cai ◽  
Pi Hui Pi ◽  
Xiu Fang Wen ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermodynamic Analysis ◽  
Hexamethylene Diisocyanate ◽  
Hydroxyethyl Methacrylate ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Fluorinated Acrylate ◽  
X Ray ◽  
Ethyl Methacrylate ◽  
Dsc Curves

In this manuscript two different fluorinated acrylate copolymers films, one was non-crosslinking Stearyl acrylate/2-(perfluorooctyl) ethyl methacrylate (SA/FOEMA) and another was cross-linked SA/2-hydroxyethyl methacrylate(HEMA)/FOEMA/hexamethylene diisocyanate trimers (N3300), were prepared and their crystallinities were investigated by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It can be shown from the XRD results that the value of crystallinities of SA/FOEMA and SA/HEMA/FOEMA/N3300 copolymer were 80.95% and 84.02%, respectively. Based on DSC curves and theoretical thermodynamic analysis , it is indicated that crosslinking can improve crystallinity of copolymer composed of SA and FOEMA.

Thermal Response of Activated Charcoal Modified Investment Casting Moulds

2015 ◽  
Vol 1125 ◽  
pp. 181-185
Author(s):  
Bashir Yahaya ◽  
E.M. Nazim ◽  
Mohd Hasbullah Idris ◽  
M.S. Dambatta ◽  
Mahmood Anwar ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Behaviour ◽  
Investment Casting ◽  
Activated Charcoal ◽  
Thermal Response ◽  
Heat Distribution ◽  
Scanning Calorimetry ◽  
Two Samples ◽  
Significant Difference ◽  
Dsc Curves

Direct microwave dewaxing of investment casting moulds is possible at the expense of time and poor heat distribution. Modifying the back-up stucco of investment casting moulds may enhance microwave absorption; however, it may affect its thermal properties. In this study, the effects of adding activated charcoal in the back-up stucco of the investment casting mould were investigated. Samples prepared without and with 25% activated charcoal were tested for differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). It was observed that the specific heat capacity is higher in the samples added with activated charcoal. The DSC curves exhibit a smooth trend with no indication of exothermic or endothermic peaks in both samples. The glass transition temperature was also increased from 515.29°C to 582.24°C after modifying the contents. However, the TGA results show no significant difference in mass lost between the two samples that are about 2%. The DSC and TGA curves for both samples show similar patterns indicating that there is very close similarity in their thermal behaviour. Due to that, it can be concluded that the addition of activated charcoal in the back-up stucco does not induce an unusual reaction or thermal behaviour in the moulds.

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