Rapid Consolidation of Hf Doped NiTi for High Transformation Temperatures

Aerospace ◽  
2004 ◽  
Author(s):  
Gang Wang ◽  
Norman Wereley ◽  
Liyang Dai ◽  
Manfred Wuttig ◽  
Raffi Sahul ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Phase Transformation ◽  
Elevated Temperatures ◽  
Plasma Pressure ◽  
Compaction Process ◽  
Transformation Temperatures ◽  
Heat Treated ◽  
High Transformation ◽  
High Transformation Temperature ◽  
Scanning Electron

The objective of this study is to develop high transformation temperature shape memory alloys (SMAs) for actuation applications at elevated temperatures. We developed a process to consolidate NiTi micron powders doped with Hf using Material Modification Inc.’s (MMI) proprietary Plasma Pressure Compaction process (P2C). NiTi and NiTiHf samples were characterized to identify the material’s microstructure and composition using Scanning Electron Microscopy (SEM) and Energy Dissipative Spectroscopy (EDS) for both as consolidated and heat treated materials. Chemical and porosity analyses were also conducted to track impurities and microstructure (grain size and porosity). Extensive thermo-mechanical testing of the NiTi and NiTiHf samples were conducted to determine phase transformation temperatures and mechanical properties (Young’s Modulus). An acoustic elastometer was used to obtain the phase transformation temperatures for both NiTi and NiTiHf samples. By doping the SMA powder with 10% Hf (atomic percent), we were able to realize an increase in the austenite finish temperature to over 160 C.

A New Method for Synthesis of FeMnO3 Ceramics and its Phase Transformation

2015 ◽  
Vol 37 ◽  
pp. 122-131 ◽  
Author(s):  
Zhi Jie Li ◽  
Shi Fa Wang ◽  
Bo Li ◽  
Xia Xiang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Phase Transformation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heat Treated ◽  
Average Coefficient ◽  
Modified Polyacrylamide ◽  
Scanning Electron

FeMnO3 powders were synthesized through a modified polyacrylamide gel route. The gel and the heat treated final powders have been characterized by X-ray diffractometry (XRD), differential scanning calorimetry and thermogravimetric analysis (TG/DSC) and field-emission scanning electron microscopy (SEM). Phase transformation sequence of dry gel during heating is (Mn+3,Fe+3)2O3→(α-Mn2O3)·(α-Fe2O3)→FeMnO3. The thermal expansion properties of as-prepared sample were determined. From 100 to 700 °C, the average coefficient of expansion is 9.0139×10-6 /K. The experimental results demonstrates that the FeMnO3 sample exhibit a ferromagnetic transitions with TN ≈ 40 K.

PHASE TRANSFORMATION AND MICROSTRUCTURE BEHAVIOUR OF CU-AL-NI SHAPE MEMORY ALLOYS INCORPORATED WITH COBALT ADDITION

2015 ◽  
Vol 74 (10) ◽  
Author(s):  
Y. C. Wee ◽  
T. Abubakar ◽  
E. Hamzah ◽  
Safaa N. Saud
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Transformation ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transformation Temperatures ◽  
X Ray ◽  
Co Addition ◽  
Cobalt Addition ◽  
Scanning Electron

The effect of Co addition on phase transformation temperatures and microstructures of Cu-Al-Ni SMA were investigated via differential scanning calorimetry, field emission scanning electron microscopy corresponding with energy dispersive spectroscopy and x-ray diffraction. The results revealed that the β1’ and γ1’ phases’ morphology and orientation were varied after the addition of Co along with the presence of intermetallic compounds known as γ2. This phase was indicated using the EDS and XRD is related to the intermetallic compound of Al75Co22Ni3. In addition, the phase transformation temperatures tend to increase with the addition of Co and this enhancement is mainly attributed to the variation of phase morphology and the existence of γ2 precipitates. 

scholarly journals Phase Relations in the ZrO2-MgO-FeOx System: Experimental Data and Assessment of Thermodynamic Parameters

2021 ◽  
Author(s):  
Ivan Saenko ◽  
O. Fabrichnaya
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
Solid Solution ◽  
Thermodynamic Parameters ◽  
Spinel Phase ◽  
Experimental Investigations ◽  
X Ray ◽  
Heat Treated ◽  
Preliminary Phase ◽  
Scanning Electron

AbstractThermodynamic parameters were assessed for the MgO–FeOx system and combined with already available descriptions of ZrO2-FeOx and ZrO2-MgO systems to calculate preliminary phase diagrams for planning experimental investigations. Samples of selected compositions were heat treated at 1523, 1673 and 1873 K and characterized using x-ray and scanning electron microscopy combined with energy dispersive x-ray spectroscopy (SEM/EDX). Experiments indicated extension of cubic ZrO2 solid solution into the ternary system at 1873 K (75 mol.% ZrO2, 10 mol.% FeOx and 15 mol.% MgO) and limited solubility of 4 mol.% ZrO2 in spinel phase. Based on the obtained results thermodynamic parameters of C-ZrO2 and spinel phase were optimized.

Microstructure Evolution and Mechanical Properties of an Al-Cu-Mg Alloy at Elevated Temperature

2014 ◽  
Vol 1004-1005 ◽  
pp. 148-153
Author(s):  
Min Hao ◽  
Ji Gang Ru ◽  
Ming Liu ◽  
Kun Zhang ◽  
Liang Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Shear Fracture ◽  
S Phase ◽  
Mg Alloy ◽  
Transmission Electron ◽  
Fracture Features ◽  
Scanning Electron

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were utilized to study the microstructure and mechanical behavior of an Al-Cu-Mg alloy after tensile test at 125°C, 150°C, 175°C and 200 °C, respectively. The yield strength and ultimate tensile strength decreased with the increase of temperature, while the elongation increased firstly and then decreased. The S and S′ precipitate after tension at elevated temperatures. When the temperature was higher than 175°C, the precipitate coarsens rapidly. The alloys displayed a shear fracture features at elevated temperature. The larger S′ and S phase coarsened and dropped which forming crack in the grain boundaries and precipitate interfaces, resulting in the decrease of the elongation of the alloy.

Precipitation study of heat-treated Incoloy 825 by scanning electron microscopy

1992 ◽  
Vol 11 (14) ◽  
pp. 1009-1011 ◽  
Author(s):  
M. A. Shaikh ◽  
M. Iqbal ◽  
M. Ahmad ◽  
J. I. Akhtar ◽  
K. A. Shoaib
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Heat Treated ◽  
Incoloy 825 ◽  
Scanning Electron

Evaluation of 4330M Steel for Fasteners Applications

2017 ◽  
Vol 380 ◽  
pp. 198-211 ◽  
Author(s):  
A. Al Sumait ◽  
C. Delgado ◽  
F. Aldhabib ◽  
X. Sun ◽  
F. Alzubi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Testing ◽  
Grain Structure ◽  
Hardness Testing ◽  
Heat Treated ◽  
Different Types ◽  
Strength And Ductility ◽  
Scanning Electron

The objective of the study was to optimize the strength and ductility values of the 4330M steel. Optimization was conducted through different types of heat treatments. Tensile testing, hardness testing, optical microscopy, and Scanning Electron Microscopy (SEM) were used to evaluate the mechanical properties and microstructure of the as-received and the heat treated samples. The alloy was provided from two vendors; vendor H and vendor S. Results showed that by increasing the tempering temperatures, strength values decreases, while ductility values remain unchanged. Vendor H samples had higher strength values and much finer grain structure which was revealed only at 5000x magnification.

Microstructural Characterisation by Scanning Electron Microscopy of Spray Formed Al/SiCp Matrix Composite

2005 ◽  
Vol 498-499 ◽  
pp. 251-257 ◽  
Author(s):  
E.G. Gomes ◽  
J.L. Rossi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Volume Fraction ◽  
Spray Forming ◽  
Heat Treated ◽  
The Matrix ◽  
Microstructural Characterisation ◽  
Silicon Carbide Particles ◽  
Carbide Particles ◽  
Scanning Electron

The material used in this work was produced by spray forming AA7475 aluminium alloy and co-depositing silicon carbide particles (20% volume fraction). The spray formed composite billets were hot extruded into round bars. The microstructure was examined in the as received and heat treated (annealed, aged, and overaged) conditions by scanning electron microscopy. Scanning electron microscopy revealed an extensive Mg2Si phase precipitation at the Al/SiCp interface due probably to Mg segregation from the matrix to the interface, during the heat treatments.

The Study of Contamination and Coarsening in Sintering Silicon Powder

2012 ◽  
Vol 557-559 ◽  
pp. 1197-1200
Author(s):  
Jung Ting Tsai ◽  
Cheng Yu Han ◽  
Shung Tian Lin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Particle Size ◽  
Vapor Pressure ◽  
Crystalline Structure ◽  
Sintering Temperature ◽  
Silicon Powder ◽  
High Density ◽  
Heat Treated ◽  
Scanning Electron

The goal of this study was to investigate the sintering mechanism of Si powder, with the particle size of Si, sintering temperature, and sintering environment as the variables. The use of a crucible, by controlling the vapor atmosphere at certain temperatures, coarsened the silicon powder. Experiment of data show that by avoiding the vapor pressure of crucible a sintering at 1380°C causes the silicon powder easily to sinter to high density, without the use of any doping addition. Therefore it is to our advantage to discover the microstructure phenomenon of silicon powder and reveal its nature. The crystalline structure of the heat-treated samples was studied with Scanning electron microscopy (SEM) to explain the resultant of contamination that causes the densification.

Sign in / Sign up

Export Citation Format

Share Document