The growth behavior of columnar grains in a TiAl alloy during directional induction heat treatments

CrystEngComm ◽  
2020 ◽  
Vol 22 (7) ◽  
pp. 1188-1196 ◽  
Author(s):  
Yangli Liu ◽  
Xiang Xue ◽  
Hongze Fang ◽  
Yingmei Tan ◽  
Ruirun Chen ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Tial Alloy ◽  
Heat Treatments ◽  
Growth Behavior ◽  
Interface Tension ◽  
Induction Heat ◽  
Columnar Grains

In the process of DHT, the curving grain boundary will move towards curvature center of grain under the action of interface tension.

Nucleation and Growth Behavior of Quaternary-Sputtered Copper Indium Gallium Diselenide Thin Films

2012 ◽  
Vol 1447 ◽  
Author(s):  
Jason D. Myers ◽  
Jesse A. Frantz ◽  
Robel Y. Bekele ◽  
Vinh Q. Nguyen ◽  
Allan Bruce ◽  
...  
Keyword(s):  
Rf Magnetron Sputtering ◽  
Production Method ◽  
Growth Behavior ◽  
Copper Indium Gallium Diselenide ◽  
Interfacial Layers ◽  
Force Microscopy ◽  
Alternative Technologies ◽  
Atomic Force ◽  
Columnar Grains ◽  
Grain Growth Behavior

AbstractIn the past two decades, the growing global demand for solar energy has spurred scientific interest in alternative technologies to conventional silicon. In particular, CuIn1-xGaxSe2 (CIGS) has emerged as a competitor. We have developed a scalable deposition technique using RF magnetron sputtering of quaternary CIGS. Notably, the resulting films do not require postselenization, reducing processing time and cost. We have fabricated devices above 10% efficiency using this approach, showing its promise as a production method for highperformance CIGS photovoltaics. However, the morphology of the sputtered CIGS layer is markedly different from conventional evaporated films; grain sizes vary through the thickness of the film, with numerous small grains dominating at the Mo/CIGS interface that then either terminate or grow in an inverted-pyramid fashion to form large, columnar grains at the CIGS/CdS interface.To better understand the origin of this morphology, we have studied the growth behavior of the CIGS layer using a combination of atomic force microscopy and electron microscopy to observe initial nucleation and grain growth behavior of quaternary-sputtered CIGS. We also discuss the effects of interfacial layers at the Mo/CIGS interface, demonstrating a novel wetting layer that conformally coats the Mo surface.

scholarly journals Molecular Dynamics Simulation on Creep Behavior of Nanocrystalline TiAl Alloy

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1693
Author(s):  
Fei Zhao ◽  
Jie Zhang ◽  
Chenwei He ◽  
Yong Zhang ◽  
Xiaolei Gao ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Grain Size ◽  
Steady State ◽  
High Temperature ◽  
Grain Boundary ◽  
Tial Alloy ◽  
Boundary Diffusion ◽  
Dislocation Motion ◽  
High Temperature Creep ◽  
Creep Stage

TiAl alloy represents a new class of light and heat-resistant materials. In this study, the effect of temperature, pressure, and grain size on the high-temperature creep properties of nanocrystalline TiAl alloy have been studied through the molecular dynamics method. Based on this, the deformation mechanism of the different creep stages, including crystal structure, dislocation, and diffusion, has been explored. It is observed that the high-temperature creep performance of nanocrystalline TiAl alloy is significantly affected by temperature and stress. The higher is the temperature and stress, the greater the TiAl alloy’s steady-state creep rate and the faster the rapid creep stage. Smaller grain size accelerates the creep process due to the large volume fraction of the grain boundary. In the steady-state deformation stage, two kinds of creep mechanisms are manly noted, i.e., dislocation motion and grain boundary diffusion. At the same temperature, the creep mechanism is dominated by the dislocation motion in a high-stress field, and the creep mechanism is dominated by the diffusion creep in the low-stress field. However, it is observed to be mainly controlled by the grain boundary diffusion and lattice diffusion in the rapid creep stage.

scholarly journals Inverse Model for the Control of Induction Heat Treatments

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2826 ◽  
Author(s):  
Asadzadeh ◽  
Raninger ◽  
Prevedel ◽  
Ecker ◽  
Mücke
Keyword(s):  
Power Level ◽  
Measurement Data ◽  
Heat Treatments ◽  
Cylindrical Sample ◽  
Inverse Model ◽  
Test Rig ◽  
Induction Heat ◽  
Current Frequency ◽  
Dependent Parameter ◽  
Heating Test

In this work, we present and test an approach based on an inverse model applicable to the control of induction heat treatments. The inverse model is comprised of a simplified analytical forward model trained with experiments to predict and control the temperature of a location in a cylindrical sample starting from any initial temperature. We solve the coupled nonlinear electromagnetic-thermal problem, which contains a temperature dependent parameter α to correct the electromagnetic field on the surface of a cylinder, and as a result effectively the modeled temperature elsewhere in the sample. A calibrated model to the measurement data applied with the process information such as the operating power level, current, frequency, and temperature provides the basic ingredients to construct an inverse model toolbox, which finally enables us to conduct experiments with more specific goals. The input set values of the power supply, i.e., the power levels in the test rig control system, are determined within an iterative framework to reach specific target temperatures in prescribed times. We verify the concept on an induction heating test rig and provide two examples to illustrate the approach. The advantages of the method lie in its simplicity, computationally cost effectiveness and independence of a prior knowledge of the internal structure of power supplies.

Void Growth Behavior in ULSI Cu Interconnections by Grain-Boundary Diffusion Simulation

2010 ◽  
Vol 39 (10) ◽  
pp. 2255-2266
Author(s):  
Takashi Onishi ◽  
Masao Mizuno ◽  
Tetsuya Yoshikawa ◽  
Jun Munemasa ◽  
Takao Inoue ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Void Growth ◽  
Boundary Diffusion ◽  
Growth Behavior ◽  
Grain Boundary Diffusion ◽  
Diffusion Simulation

Study on the growth behavior of voids located at the grain boundary

2009 ◽  
Vol 41 (7) ◽  
pp. 799-809 ◽  
Author(s):  
Wenhui Liu ◽  
Xinming Zhang ◽  
Jianguo Tang
Keyword(s):  
Grain Boundary ◽  
Growth Behavior

Fatigue crack growth behavior of wrought γ-based TiAl alloy containing β-phase

2018 ◽  
Vol 100 ◽  
pp. 77-87 ◽  
Author(s):  
Loris Jonathan Signori ◽  
Taiki Nakamura ◽  
Yotaro Okada ◽  
Ryosuke Yamagata ◽  
Hirotoyo Nakashima ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Tial Alloy ◽  
Growth Behavior ◽  
Crack Growth Behavior ◽  
Fatigue Crack Growth Behavior ◽  
Β Phase

scholarly journals Machine Learning for Competitive Grain Growth Behavior in Additive Manufacturing Ti6Al4V

2020 ◽  
Vol 321 ◽  
pp. 03004
Author(s):  
Jinghao Li ◽  
Manuel Sage ◽  
Xianglin Zhou ◽  
Mathieu Brochu ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Additive Manufacturing ◽  
Grain Boundary ◽  
Grain Growth ◽  
Manufacturing Industry ◽  
Energy Deposition ◽  
Growth Behavior ◽  
Direct Energy Deposition ◽  
Direct Energy ◽  
Grain Growth Behavior ◽  
Metal Additive

Metal additive manufacturing (MAM) technology is now changing the pattern of the high-end manufacturing industry, among which MAM fabricated Ti6Al4V has been far the most extensively investigated material and attracts a lot of research interests. This work established a deep neural network (DNN) to investigate the grain boundary in competitive grain growth for a bi-crystal system, the column β grains of Ti6Al4V as an example. Because of the limited number of experimental samples, the DNN is trained based on the data coming from the Geometrical Limited criterion. A series of direct energy deposition experiment using Ti6Al4V is carried out under the Taguchi experimental design. The grain boundary angles between the column grains are measured in the experiment and used to evaluate the accuracy of DNN.

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