Morphology and Texture of Chemical-Vapour-Deposited TiN Films

1997 ◽  
Vol 472 ◽  
Author(s):  
Noboru Yoshikawa ◽  
Shoji Taniguchi ◽  
Atsushi Kikuchi
Keyword(s):  
Crystal Orientation ◽  
Chemical Vapour ◽  
Deposition Process ◽  
Grain Structure ◽  
Similar Time ◽  
Tin Films ◽  
Grain Structures ◽  
Structure Morphology ◽  
Columnar Grains ◽  
Zone Ii

ABSTRACTTiN films were obtained by Chemical Vapour Depositon (CVD) under different deposition conditions. Their grain structure, morphology and preferred crystal orientation were investigated. It was observed that well-defined columnar grams developed under conditions of atmospheric thermal CVD, giving rise to strong preferred orientations. In this study, grain structures of CVD-TiN films were classified with respect to the substrate temperature. Films of zone I structure were obtained at 1173K (0.35Tm), and those of zone II were obtained at 1223K (0.38Tm). Crystal shape of the zone II columnar grains was influenced by the partial pressure of TiCl4 (PTiCl4), and the crystal orientation of films was related to the crystal shapes. Columnar grains increased their thickness during deposition process under conditions of low PTiC14 and high temperature (>1250K). The increase rate of grain size had a similar time dependence to that of normal grain growth. The “quadrangular-shaped” and “star-shaped” columnar crystals were formed. They consisted of several crystals and contained twins. Their microstructures were observed in relation to their crystallographic features.

The Challenges Associated with the Formation of Equiaxed Grains during Additive Manufacturing of Titanium Alloys

2018 ◽  
Vol 770 ◽  
pp. 155-164 ◽  
Author(s):  
David H. St John ◽  
Stuart D. McDonald ◽  
Michael J. Bermingham ◽  
Sri Mereddy ◽  
Arvind Prasad ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Temperature Gradients ◽  
Metal Alloys ◽  
Grain Structure ◽  
Grain Structures ◽  
Columnar Grains ◽  
High Cooling Rates ◽  
Columnar Grain ◽  
Equiaxed Grains ◽  
Equiaxed Grain

It is well established that columnar grain structures usually form when metal alloys are used to additively manufacture components. A challenging goal is to produce an equiaxed grain structure throughout the component to remove anisotropy and refine the grain size in order to improve its mechanical performance. The high cooling rates and associated high temperature gradients are the main reasons for the formation of columnar grains via epitaxial growth of each added layer of material. There appear to be limited strategies for promoting equiaxed nucleation of grains. In addition to cooling rate and temperature gradient, we explore other variables such as the potency of natural or added inoculant particles and the composition of the alloy, and their possible impact on the nucleation of equiaxed grains. Although changing the composition can help, finding a suitably potent nucleant particle is a major challenge. Operating parameters can also influence the microstructure and optimization to produce equiaxed grains may be possible. The limitations of these strategies and possible ways to overcome them are evaluated.

scholarly journals Grain structure control during metal 3D printing by high-intensity ultrasound

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
C. J. Todaro ◽  
M. A. Easton ◽  
D. Qiu ◽  
D. Zhang ◽  
M. J. Bermingham ◽  
...  
Keyword(s):  
3D Printing ◽  
High Intensity ◽  
Grain Structure ◽  
Model Alloy ◽  
High Intensity Ultrasound ◽  
Structure Control ◽  
Grain Structures ◽  
Columnar Grains ◽  
Metal 3D Printing ◽  
Columnar Grain

AbstractAdditive manufacturing (AM) of metals, also known as metal 3D printing, typically leads to the formation of columnar grain structures along the build direction in most as-built metals and alloys. These long columnar grains can cause property anisotropy, which is usually detrimental to component qualification or targeted applications. Here, without changing alloy chemistry, we demonstrate an AM solidification-control solution to printing metallic alloys with an equiaxed grain structure and improved mechanical properties. Using the titanium alloy Ti-6Al-4V as a model alloy, we employ high-intensity ultrasound to achieve full transition from columnar grains to fine (~100 µm) equiaxed grains in AM Ti-6Al-4V samples by laser powder deposition. This results in a 12% improvement in both the yield stress and tensile strength compared with the conventional AM columnar Ti-6Al-4V. We further demonstrate the generality of our technique by achieving similar grain structure control results in the nickel-based superalloy Inconel 625, and expect that this method may be applicable to other metallic materials that exhibit columnar grain structures during AM.

Magnetic and Mechanical Properties of Directionally Solidified Fe-6.5wt.%Si Alloy

2011 ◽  
Vol 687 ◽  
pp. 122-128
Author(s):  
Y. S. Deng ◽  
Xian Shi Fang ◽  
Feng Ye ◽  
Y. Qiao ◽  
Jun Pin Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Directional Solidification ◽  
Grain Growth ◽  
Magnetic Induction ◽  
Crystal Orientation ◽  
Grain Structure ◽  
Directionally Solidified ◽  
Columnar Grains ◽  
Columnar Grain ◽  
Saturation Magnetic Induction

Directional solidification technique was employed to produce Fe-6.5wt.%Si alloy with coarse columnar-grain structure, which was almost single crystal. The sectional diameters of columnar grains range from 2.2 to 6.8 mm. The saturation magnetic induction was 2.39 T. In this work, grain growth started from either a Fe-6.5wt.%Si crystal which was not melted at bottom of the specimen or a freely nucleated Fe-6.5wt.%Si crystal as the specimen was completely melted. It was found that the starting situation of the directional solidification plays an important role in the crystal orientation, and hence in properties.

scholarly journals Crystal Orientation-Dependent Oxidation of Epitaxial TiN Films with Tunable Plasmonics

ACS Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 847-856
Author(s):  
Ruyi Zhang ◽  
Qian-Ying Ma ◽  
Haigang Liu ◽  
Tian-Yu Sun ◽  
Jiachang Bi ◽  
...  
Keyword(s):  
Crystal Orientation ◽  
Tin Films

Formation of Grain Structures of Thermal Sprayed Nickel Coatings and the Coating Properties

2005 ◽  
Vol 502 ◽  
pp. 517-0
Author(s):  
Kenji Murakami
Keyword(s):  
Steel Substrate ◽  
Nickel Coatings ◽  
Grain Structures ◽  
Heat Treated ◽  
Columnar Grains ◽  
Different Temperatures ◽  
Plasma Sprayed ◽  
Equiaxed Grains ◽  
Sprayed Coatings ◽  
Lamellar Interfaces

Pure nickel powder was low pressure plasma sprayed onto a steel substrate held at different temperatures during spraying. The as-sprayed coatings consist of columnar grains whose axes are nearly perpendicular to the lamellae composing the coatings. As the coating temperature becomes higher, the length of the columnar grains increases and is longer than the thickness of the lamellae, indicating the growth of the grains across the lamellar interfaces during spraying. On the other hand, the coatings that were heat treated after spraying consist of coarse equiaxed grains. The coatings that experienced high temperatures during spraying or the heat treated coatings have large porosity and contain large globular pores. The hardness, apparent density and the tensile strength of the coating itself were the highest for the coating prepared at a low temperature and became low on heat treatment. The thermal conductivity in the direction perpendicular to the coating was the largest for the coating that consisted of long columnar grains.

Evaluation of Cutting Force and Surface Roughness in Turning of GFRP Using Coated Carbide Insert

2015 ◽  
Vol 813-814 ◽  
pp. 317-321 ◽  
Author(s):  
C. Ramesh Kannan ◽  
P. Padmanabhan ◽  
K.P. Vasanthakumar
Keyword(s):  
Surface Roughness ◽  
Glass Fiber ◽  
Cutting Force ◽  
Chemical Vapour ◽  
Deposition Process ◽  
Depth Of Cut ◽  
Reinforced Plastics ◽  
Coated Carbide ◽  
Machining Parameter ◽  
Carbide Insert

This paper is to evaluate the cutting force and surface roughness in turning of Glass fiber reinforced plastics (E-glass fiber) using coated carbide insert. The comparison of the results with uncoated carbide inserts. The carbide insert is coated by multilayer chemical vapour deposition process, the coating elements are TiN/Al2O3/TiCN. The experiment is carried out in the conventional lathe machine under dry condition by varying the three cutting parameter such as speed, feed and depth of cut. The cutting force is measured using a lathe tool dynamometer and surface roughness are measured by using surf tester.The result of the experiment shows the effect of machining parameter on cutting force and surface roughness. The results have confirmed that the coated carbide insert has better results than uncoated and tool life is increased.

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