scholarly journals Quench Sensitivity and Phase Transformation Kinetics of AlSi7MnMg High Pressure Vacuum Die Casting

2020 ◽  
Vol 326 ◽  
pp. 02001
Author(s):  
Mengyun Liu ◽  
Zhan Zhang ◽  
Francis Breton ◽  
X.-Grant Chen
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Mechanical Strength ◽  
Isothermal Treatment ◽  
Transformation Rate ◽  
Temperature Property ◽  
Quench Sensitivity ◽  
Transformation Diagrams ◽  
Nose Temperature ◽  
Kinetics Of

The quench sensitivity of an AlSi7MnMg alloy in high-pressure vacuum die (HPVD) casting was investigated by time-temperature-transformation and time-temperature-property diagrams with an interrupted quench technique. The quench sensitive temperature range of the alloy is from 260 to 430 °C and its nose temperature is 350 °C. The mechanical strength versus cooling rates of the HPVD casting was predicted using quench factor analysis method and verified by experimental results. The critical cooling rate is 6 °C/s to remain 95% of the maximal mechanical strength. The coefficients k2 - k5, related to the nucleation and precipitation kinetics of TTP curves, and phase transformation diagrams were determined. The precipitation of Mg2Si phase in the castings was observed during isothermal treatment using transmission electron microscope. Moreover, the quench sensitivity and kinetics of the phase transformation of AlSi7MnMg alloy and AlSi10MnMg alloys were compared. It reveals that the quench sensitivity and phase transformation rate of the former are lower than that of the latter.

scholarly journals Investigation of the Quench Sensitivity of an AlSi10Mg Alloy in Permanent Mold and High-Pressure Vacuum Die Castings

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1876 ◽  
Author(s):  
Mengyun Liu ◽  
Zhan Zhang ◽  
Francis Breton ◽  
X.-Grant Chen
Keyword(s):  
High Pressure ◽  
Cooling Rate ◽  
Aluminum Matrix ◽  
Critical Time ◽  
Permanent Mold ◽  
Temperature Property ◽  
Critical Cooling Rate ◽  
Quench Sensitivity ◽  
Die Castings ◽  
Nose Temperature

The quench sensitivities of an AlSi10Mg alloy in permanent mold (PM) and high-pressure vacuum die (HPVD) castings were investigated with time–temperature–transformation and time–temperature–property diagrams using an interrupted quench technique. The quench-sensitive temperature range of the HPVD casting sample is 275–450 °C, and its nose temperature is 375 °C. The quench-sensitive range of the PM casting sample is 255–430 °C, and the nose temperature is 350 °C. The mechanical strength versus the cooling rate in both casting samples were predicted via a quench factor analysis and verified experimentally. The critical cooling rate of the HPVD casting sample is 20 °C/s whereas it is 17 °C/s for the PM casting sample. With a shorter critical time, higher nose temperature, and higher critical cooling rate, the HPVD casting sample exhibits a higher quench sensitivity than the PM casting sample. The differences in the quench sensitivities of the AlSi10Mg alloy due to the different casting processes is explained via the different precipitation behavior. At the nose temperature, coarse β-Mg2Si precipitates mainly precipitate along the grain boundaries in the HPVD casting sample, whereas rod-like β-Mg2Si precipitates distribute in the aluminum matrix in the PM casting.

Kinetics of the Wurtzite-to-Rock-Salt Phase Transformation in ZnO at High Pressure

2011 ◽  
Vol 115 (17) ◽  
pp. 4354-4358 ◽  
Author(s):  
Vladimir L. Solozhenko ◽  
Oleksandr O. Kurakevych ◽  
Petr S. Sokolov ◽  
Andrey N. Baranov
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Rock Salt ◽  
Salt Phase ◽  
Kinetics Of

Kinetics of hexagonal–cubic phase transformation of zinc sulfide in vacuo, in zinc vapor, and in sulfur vapor

1968 ◽  
Vol 46 (18) ◽  
pp. 2881-2886 ◽  
Author(s):  
Tamas Bansagi ◽  
E. A. Secco ◽  
O. K. Srivastava ◽  
Ronald R. Martin
Keyword(s):  
Phase Transformation ◽  
Zinc Sulfide ◽  
Solid Phase ◽  
Cubic Phase ◽  
Transformation Rate ◽  
Zinc Vapor ◽  
Sulfur Vapor ◽  
Diffusion Controlled ◽  
Transformation Reaction ◽  
Kinetics Of

The kinetics of the hexagonal–cubic phase transformation of zinc sulfide have been studied in vacuo, in zinc vapor, and in sulfur vapor in the temperature range 800–900 °C by a powder X-ray diffraction technique. The transformation rate is enhanced in the presence of sulfur and zinc vapor. In vacuo and in sulfur vapor the reaction is nucleation-controlled with activation energies of 95.0 and 98.5 ± 5 kcal, respectively. In zinc vapor the reaction is diffusion-controlled with the diffusion coefficient expressed as[Formula: see text]The modes of catalytic action by sulfur and zinc vapor on the solid phase transformation reaction are discussed.

Phase Transformation Kinetics of Austenite during a Combination of Laser-Hybrid and Multi-Arc Welding of High Pressure Pipes

2020 ◽  
Vol 121 (10) ◽  
pp. 996-1001
Author(s):  
L. A. Efimenko ◽  
O. E. Kapustin ◽  
D. V. Ponomarenko ◽  
I. Yu. Utkin ◽  
A. I. Romantsov ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Arc Welding ◽  
Transformation Kinetics ◽  
Phase Transformation Kinetics ◽  
Pressure Pipes ◽  
Laser Hybrid ◽  
Kinetics Of

scholarly journals Effect of Cold Rolling on the Phase Transformation Kinetics of an Al0.5CoCrFeNi High-Entropy Alloy

Entropy ◽  
2018 ◽  
Vol 20 (12) ◽  
pp. 917 ◽  
Author(s):  
Jun Wang ◽  
Haoxue Yang ◽  
Tong Guo ◽  
Jiaxiang Wang ◽  
William Yi Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Expansion ◽  
Phase Transformation ◽  
Cold Rolling ◽  
High Entropy Alloy ◽  
Transformation Rate ◽  
Transformation Kinetics ◽  
High Entropy ◽  
Phase Transformation Kinetics ◽  
Kinetics Of

The solid state phase transformation kinetics of as-cast and cold rolling deformed Al0.5CoCrFeNi high-entropy alloys have been investigated by the thermal expansion method. The phase transformed volume fractions are determined from the thermal expansion curve using the lever rule method, and the deformed sample exhibits a much higher transformation rate. Two kinetic parameters, activation energy (E) and kinetic exponent (n) are determined using Kissinger– Akahira–Sunose (KAS) and Johnson–Mehl–Avrami (JMA) method, respectively. Results show that a pre-deformed sample shows a much lower activation energy and higher kinetic exponent compared with the as-cast sample, which are interpreted based on the deformation induced defects that can promote the nucleation and growth process during phase transformation.

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