scholarly journals The influence of the melting regime on oxygen deposition from powders of naturally alloyed iron

2016 ◽  
Vol 16 (02) ◽  
pp. 23-27
Author(s):  
E.E. Baryshev ◽  
◽  
G.V. Tyagunov ◽  
Keyword(s):  
Alloyed Iron ◽  
Melting Regime

Epitaxial Growth Following Crystal Nucleation in Laser-Quenched Si Films on SiO2

2015 ◽  
Vol 1770 ◽  
pp. 67-72
Author(s):  
Vernon K. Wong ◽  
A. M. Chitu ◽  
A. B. Limanov ◽  
James S. Im
Keyword(s):  
Epitaxial Growth ◽  
Growth Model ◽  
Crystal Nucleation ◽  
Key Factors ◽  
Complete Melting ◽  
Melting Regime ◽  
Direct Growth ◽  
Crystal Core ◽  
Excimer Laser Irradiation ◽  
Si Films

ABSTRACTWe have investigated the solidified microstructure of nucleation-generated grains obtained via complete melting of Si films on SiO2 at high nucleation temperatures. This was achieved using a high-temperature-capable hot stage in conjunction with excimer laser irradiation. As predicted by the direct-growth model that considers (1) the evolution in the temperature of the solidifying interface and (2) the subsequent modes of growth (consisting of amorphous, defective, and epitaxial) as key factors, we were able to observe the appearance of “normal” grains that possess a single-crystal core area. These grains, which are in contrast to previously reported flower-shaped grains that fully make up the microstructure of the solidified films obtained via irradiation at lower preheating temperatures (and amongst which these “normal” grains emerge), indicate that epitaxial growth of nucleated crystals must have taken place within the grains. We discuss the implications of our findings regarding (1) the validity of the direct-growth model, (2) the nature of the heterogeneous nucleation mechanism, and (3) the alternative explanations and assumptions that have been previously employed in order to explain the microstructure of Si films obtained via nucleation and growth within the complete melting regime.

Diffusion-alloying sintering of Cr–Mo pre-alloyed iron powders with carbon: The effect of the carbon introduction method on the sinter’s properties

2021 ◽  
Vol 112 (1) ◽  
pp. 48-56
Author(s):  
Lubomir Anestiev ◽  
Jordan Georgiev ◽  
Seryozha Valkanov ◽  
Marcela Selecká ◽  
Sabine Cherneva ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Dissolution Rate ◽  
Reasonable Assumption ◽  
Micro Structure ◽  
Iron Powders ◽  
Base Powder ◽  
Alloyed Iron ◽  
Iron Based

Abstract The influence of the carbon introduction method on the microstructure and the mechanical properties of sinters produced from iron-based powders by diffusion-alloying sintering has been studied. Two methods of carbon introduction were tested: (1) Premixing of the base powder with graphite, and (2) Coating of the base powder with a carbon-containing substance. The results obtained could be summarized as (1) The microstructure and the mechanical properties depend on the method of carbon introduction; (2) The sinters produced from coated powders possess finer micro-structure, improved homogeneity, and in two out of three of the studied compositions, better mechanical properties. Based on the results obtained, a reasonable assumption was made that the method of carbon introduction affects the dissolution rate of the carbon additive, thus affecting the micro-structure and the mechanical properties of the sinter.

scholarly journals Characterization and Prediction of Texture in Laser Annealed NiTi Shape Memory Thin Films

2010 ◽  
Author(s):  
Gen Satoh ◽  
Y. Lawrence Yao ◽  
Xu Huang ◽  
Ainissa Ramirez
Keyword(s):  
Thin Film ◽  
Monte Carlo ◽  
Shape Memory ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Laser Crystallization ◽  
3 Dimensional ◽  
Shape Memory Properties ◽  
Melting Regime ◽  
Grain Growth Model

Thin film shape memory alloys are a promising material for use in micro-scale devices for actuation and sensing due to their strong actuating force, substantial displacements, and large surface to volume ratios. NiTi, in particular, has been of great interest due to its biocompatibility and corrosion resistance. Effort has been directed toward adjusting the microstructure of as-deposited films in order to modify their shape memory properties for specific applications. The anisotropy of the shape memory and superelastic effects suggests that inducing preferred orientations could allow for optimization of shape memory properties. Limited work, however, has been performed on adjusting the crystallographic texture of these films. In this study, thin film NiTi samples are processed using excimer laser crystallization and the effect on the overall preferred orientation is analyzed through the use of electron backscatter diffraction and x-ray diffraction. A 3-dimensional Monte Carlo grain growth model is developed to characterize textures formed through surface energy induced abnormal grain growth during solidification. Furthermore, a scaling factor between Monte Carlo steps and real time is determined to aid in the prediction of texture changes during laser crystallization in the partial melting regime.

Structure and magnetic properties of mechanically alloyed iron nitride powders

1995 ◽  
Vol 222 (1-2) ◽  
pp. 179-183 ◽  
Author(s):  
Pee-Yew Lee ◽  
Tzeng-Rong Chen ◽  
Tsung-Shune Chin
Keyword(s):  
Magnetic Properties ◽  
Iron Nitride ◽  
Mechanically Alloyed ◽  
Alloyed Iron
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