scholarly journals Effects of Solidification Cooling Rate on the Microstructure of Nickel Based Superalloy GTD222

2019 ◽  
Author(s):  
Bo Gao ◽  
Yanfei Sui ◽  
Hongwei Wang ◽  
Chunming Zou ◽  
Zunjie Wei ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Alloying Elements ◽  
Solidification Behavior ◽  
Cooling Rates ◽  
Dendrite Arm Spacing ◽  
Nickel Based Superalloy

The microstructure and solidification behavior of nickel based GTD222 superalloy at different cooling rates are studied. The solidification of the GTD222 superalloy proceeds as follows: L→L+γ, L→L+γ+MC, L→L+(γ/γ ′)-Eutectic and L→η phase. The temperature of liquidus of GTD222 superalloy is 1360 °C while the solidus is slightly lower at 1310 °C, which due to the alloying elements redistribution. It was found that the dendrite arm spacing of the alloy decreased with the increase of cooling rate (From 200 μm at 2.5 K/min to 100 μm at 20 K/min).

scholarly journals Effects of Cooling Rate on the Solidification and Microstructure of Nickel-Based Superalloy GTD222

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1920
Author(s):  
Bo Gao ◽  
Yanfei Sui ◽  
Hongwei Wang ◽  
Chunming Zou ◽  
Zunjie Wei ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Solidification Behavior ◽  
Alloying Element ◽  
Cooling Rates ◽  
Dendrite Arm Spacing ◽  
Nickel Based Superalloy ◽  
Element Redistribution

In this work, the microstructure and solidification behavior of nickel-based superalloy GTD222 at different cooling rates are studied. The solidification of the superalloy GTD222 proceeds as follows: L → L + γ, L → L + γ + MC, L → L + (γ/γ′)-Eutectic and L → η phase. Due to alloying element redistribution, the temperature of the solidus GTD222 superalloy, 1310 °C, is slightly lower than the temperature of the liquidus, which is 1360 °C. It was found that the dendrite arm spacing of the alloy decreased with the increase of the cooling rate from 200 μm at 2.5 K/min to 100 μm at 20 K/min.

Achieving the Dual Phase Structure in Low Alloyed Steel with Slow Cooling Rate

2008 ◽  
Vol 575-578 ◽  
pp. 1117-1122
Author(s):  
Tarja Jäppinen ◽  
Seppo Kivivuori
Keyword(s):  
Cooling Rate ◽  
Phase Structure ◽  
Steel Wire ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Alloying Elements ◽  
Dual Phase ◽  
Low Carbon ◽  
Slow Cooling ◽  
Cooling Rates

In steel wire processing it is difficult to reach a homogenous structure throughout the cross-section of the wire particularly in greater diameters. One alternative for producing a homogenous structure is to find a cooling path with a wide transformation temperature range. Fully austenite steel wire rolled at high temperatures can be decomposed into ferritic-martensitic dual phase structure using relatively slow cooling rates. Test materials were low alloyed low carbon steels with variations in alloying elements. Gleeble-1500 thermomechanical simulator was utilised to study the effect of cooling rate on decomposition of austenite after deformation. The microstructures were studied with an optical microscope. In certain low alloyed steels slow cooling rates eliminate the bainite transformation and instead martensite is formed. The final microstructure depends mainly on the carbon content but also on the amount of other alloying elements and their effects on the austenite phase.

Effect of Cooling Rate on Structural and Chemical Microheterogeneity of IN 738LC Nickel Based Superalloy

2008 ◽  
Vol 138 ◽  
pp. 201-208 ◽  
Author(s):  
Jana Dobrovská ◽  
Simona Dočekalová ◽  
Věra Dobrovská ◽  
Karel Stránský
Keyword(s):  
Cooling Rate ◽  
Experimental System ◽  
Solidification Behavior ◽  
Ramp Rate ◽  
Concentration Data ◽  
Measured Concentration ◽  
X Ray ◽  
Nickel Based Superalloy ◽  
The Individual ◽  
Scanning Electron

The paper deals with the effect of cooling rate on solidification behavior of IN 738LC nickel based superalloy and on resulting structural and chemical microheterogeneity of this alloy. Samples taken from as-received state were heated with controlled ramp rates (1, 5, 10 and 20 °C min-1). Immediately after melting they were cooled with the same controlled ramp rate with the help of the laboratory experimental system SETARAM SETSYS 18TM TG/DTA/TMA. Then the microanalysis of minority phases was conducted with use of X-ray spectroscopy and microstructure of the individual samples was documented by scanning electron microscopy. Chemical microheterogeneity was determined on the basis of measured concentration data of selected elements (Al, Ti, Cr, Co, Ni, Nb, Mo, Ta and W) in representative areas of the individual samples structure.

Effect of Cooling Rate on the Microstructure of Al-5.17Cu-2.63Si Cast Alloy

2013 ◽  
Vol 813 ◽  
pp. 157-160
Author(s):  
Guang Wei Zhao ◽  
Xi Cong Ye ◽  
Zeng Min Shi ◽  
Wen Jun Liu
Keyword(s):  
Cooling Rate ◽  
Volume Fraction ◽  
Cast Alloy ◽  
Eutectic Phase ◽  
Cooling Curves ◽  
Cooling Rates ◽  
Dendrite Arm Spacing

The effect of cooling rate on the solicitation microstructure of a ternary cast Al-5.17Cu-2.63Si alloy is investigated. To create widely different cooling rates for the investigated alloy, the melts were cast into four molds made of different materials: aluminum, graphite, sand, and alumina-silicate-fiber felt (a thermal insulated material), respectively. The cooling curves for each mold specimen were simultaneously measured using calibrated K-type thermocouples, which are linked to a PC computer. The microstructures are characterized in terms of eutectic volume fraction and second dendrite arm spacing. The experiment result shows that increasing the cooling rate increases the amount of eutectic phase and decreases significantly the second dendrite arm spacing.

High Strength Sinter-Hardening Powder Metallurgy Alloys

2008 ◽  
Vol 51 ◽  
pp. 3-9 ◽  
Author(s):  
K.S. Hwang ◽  
M.W. Wu ◽  
Chia Cheng Tsai
Keyword(s):  
Tensile Strength ◽  
Powder Metallurgy ◽  
Cooling Rate ◽  
High Hardness ◽  
High Strength ◽  
Alloying Elements ◽  
Cooling Rates ◽  
The Matrix ◽  
Fast Cooling ◽  
The Cost

High strength and high hardness can be readily attained after sintering when sinter-hardening grade powder metallurgy alloys are used. However, fast cooling rates greater than 60°C/min are usually required. This increases the cost of the sintering equipment and maintenance. To lower the required minimum cooling rate, the homogeneity of the alloying elements in the matrix and the hardenability of the material must be improved. Among the various popular alloying elements, nickel and carbon are the two most non-uniformly distributed elements due to their repelling effect. It is found that to improve their homogenization, the addition of Cr and Mo can alleviate the repelling effect between Ni and C. As a result, weak Ni-rich/C-lean ferrite and austenite are eliminated and replaced by hard bainite and martensite. A tensile strength of 1323 MPa and a hardness of 39 HRC are attained in sinter-hardened Fe-3Cr-0.5Mo-4Ni-0.5C compacts without any quenching treatment.

Effect of Cooling Rate on Modification and Grain Refinement of 4032 Aluminum Alloy

2016 ◽  
Vol 877 ◽  
pp. 20-26
Author(s):  
Yong Fu Wu ◽  
Guang Lei Zhu ◽  
Gu Zhong ◽  
Hiromi Nagaumi
Keyword(s):  
Aluminum Alloy ◽  
Cooling Rate ◽  
Grain Refinement ◽  
Eutectic Silicon ◽  
Alloying Elements ◽  
Cooling Rates ◽  
Grain Length ◽  
Silicon Particles

Effect of cooling rate on modification and refinement of 4032 aluminum alloy has been investigated at cooling rates of 0.7~4.5 K/s. Sr is used to modify eutectic silicon and B is used to refine primary α-Al grains. Modification level of eutectic silicon and refining results of primary α-Al are characterized quantitatively by Lp based on the perimeter of eutectic silicon particles and the maximum grain length D, respectively. As the cooling rate decreases, the needle-like eutectic silicon particles increases and the modification level reduces with a constant Sr content. Influenced by alloying elements such as Mg, Cu and Ni, the modification level is very low at the lowest cooling rate of 0.7 K/s, but properly increasing Sr content in the melt can improve the modification. At the cooling rates of 0.7~4.5 K/s, the element B can transform coarse columnar dendritic α-Al grains to equiaxed ones, and controlling the ratio of Sr and B is a valid technique to avoid mutual poisoning. On the conditions of present experiments, the Sr content of 350 ppm and Sr:B ratio of about 1.1 are rational to modify eutectic silicon and refine primary α-Al grains simultaneously.

scholarly journals The Effect of Major Alloying Elements on the Size of Secondary Dendrite Arm Spacing in the As-Cast Al-Si-Cu Alloys

2012 ◽  
Vol 12 (1) ◽  
pp. 19-24 ◽  
Author(s):  
M. Djurdjevič ◽  
M. Grzinčič
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Alloy Composition ◽  
Control Structure ◽  
Alloying Elements ◽  
Comprehensive Understanding ◽  
Secondary Dendrite Arm Spacing ◽  
Dendrite Arm Spacing ◽  
Cu Alloys ◽  
Metal Treatment

The Effect of Major Alloying Elements on the Size of Secondary Dendrite Arm Spacing in the As-Cast Al-Si-Cu Alloys A comprehensive understanding of melt quality is of paramount importance for the control and prediction of actual casting characteristics. Among many phenomenon that occur during the solidification of castings, there are four that control structure and consequently mechanical properties: chemical composition, liquid metal treatment, cooling rate and temperature gradient. The cooling rate and alloy composition are most important among them. This paper investigates the effect of the major alloying elements (silicon and copper) of Al-Si-Cu alloys on the size of secondary dendrite arm spacing. It has been shown that both alloying elements have reasonable influence on the refinement of this solidification parameter.

The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Cooling Rate ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Crystalline Polymer ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Cooling Rates ◽  
Control Range ◽  
Temperature Range ◽  
Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

scholarly journals Nucleation Behavior of a Single Al-20Si Particle Rapidly Solidified in a Fast Scanning Calorimeter

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2920
Author(s):  
Qin Peng ◽  
Bin Yang ◽  
Benjamin Milkereit ◽  
Dongmei Liu ◽  
Armin Springer ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Rapid Solidification ◽  
Heterogeneous Nucleation ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Solidification Behavior ◽  
Nucleation Kinetics ◽  
Nucleation Behavior ◽  
Nucleation Undercooling ◽  
Primary Si

Understanding the rapid solidification behavior characteristics, nucleation undercooling, and nucleation mechanism is important for modifying the microstructures and properties of metal alloys. In order to investigate the rapid solidification behavior in-situ, accurate measurements of nucleation undercooling and cooling rate are required in most rapid solidification processes, e.g., in additive manufacturing (AM). In this study, differential fast scanning calorimetry (DFSC) was applied to investigate the nucleation kinetics in a single micro-sized Al-20Si (mass%) particle under a controlled cooling rate of 5000 K/s. The nucleation rates of primary Si and secondary α-Al phases were calculated by a statistical analysis of 300 identical melting/solidification experiments. Applying a model based on the classical nucleation theory (CNT) together with available thermodynamic data, two different heterogeneous nucleation mechanisms of primary Si and secondary α-Al were proposed, i.e., surface heterogeneous nucleation for primary Si and interface heterogenous nucleation for secondary α-Al. The present study introduces a practical method for a detailed investigation of rapid solidification behavior of metal particles to distinguish surface and interface nucleation.

Hardenability of Medium Carbon Cr-Mn-Mo Alloyed Steels

2019 ◽  
Vol 946 ◽  
pp. 341-345
Author(s):  
Mikhail V. Maisuradze ◽  
Maksim A. Ryzhkov
Keyword(s):  
Cooling Rate ◽  
Structural Steels ◽  
Alloying Elements ◽  
Metallographic Analysis ◽  
Medium Carbon ◽  
Austenite Transformation ◽  
Continuous Cooling ◽  
Different Content ◽  
Cct Diagrams

Three medium carbon Cr-Mn-Mo structural steels with different content of alloying elements were studied. The austenite transformation during continuous cooling was investigated using dilatometer and metallographic analysis. The CCT diagrams were plotted showing the effect of the increased alloying elements content and B and Nb micro-alloying on the hardenability of the studied steels. The hardness dependences on the cooling rate were obtained.

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