Heat Treatment Behavior of Tungsten Heavy Alloy

2006 ◽  
Vol 118 ◽  
pp. 35-40 ◽  
Author(s):  
Woon Hyung Baek ◽  
Moon Hee Hong ◽  
Eun Pyo Kim ◽  
Joon Woong Noh ◽  
Seong Lee ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Dynamic Properties ◽  
Weight Percent ◽  
Matrix Phase ◽  
Heavy Alloy ◽  
Tungsten Heavy Alloy ◽  
Cyclic Heat Treatment ◽  
Cyclic Heat ◽  
The Difference ◽  
The Impact

This paper focuses on the variations of static and dynamic properties of tungsten heavy alloy with heat treatment. The matrix phase of 93W-4.9Ni-2.1Fe (weight percent) has been penetrated into W/W grain boundaries during a cyclic heat treatment which consists of repeated isothermal holdings at 1150 °C and water quenching between them. By applying the cyclic heat treatment, the impact energy of tungsten heavy alloy is increased about three times from 57 to 170 J. When the tungsten heavy alloy is cyclically heat treated at 1150 °C and then re-sintered at 1485 °C, W/matrix interface is changed from round to undulated shape. The irregularity of the interface is increased with increasing the number of heat treatment cycles. From the measurement of the residual stress of W grains by X-ray diffraction, it is found that the irregularity of the interface is closely related with strain energy stemmed from the difference of thermal expansion coefficient between W particles and matrix phase. From dynamic ballistic test, it is found that the tungsten heavy alloy with undulated W grains forms many narrow fracture bands which are preferential for the self sharpening effect, thus, for the improvement of the penetration performance.

Concurrent Hardening and Toughening of a Tungsten Heavy Alloy via a Novel Carburizing Cyclic Heat Treatment

2021 ◽  
pp. 2001283
Author(s):  
Ke Hu ◽  
Xiaoqiang Li ◽  
Bo Liu ◽  
Shengguan Qu ◽  
Liang Liang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heavy Alloy ◽  
Tungsten Heavy Alloy ◽  
Cyclic Heat Treatment ◽  
Cyclic Heat

scholarly journals Electron beam welding of Fe–Mn–Al–Ni shape memory alloy: Microstructure evolution and shape memory response

2017 ◽  
Vol 10 (04) ◽  
pp. 1750043 ◽  
Author(s):  
P. Krooß ◽  
J. Günther ◽  
L. Halbauer ◽  
M. Vollmer ◽  
A. Buchwalder ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electron Beam ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Electron Beam Welding ◽  
Eb Welding ◽  
Cyclic Heat Treatment ◽  
Memory Response ◽  
Cyclic Heat ◽  
The Impact

The present study reports on the impact of abnormal grain growth (AGG) on the microstructural evolution following electron beam (EB) welding of Fe–Mn–Al–Ni shape memory alloy (SMA). Polycrystalline sheet-like material was EB-welded and a cyclic heat treatment, studied in previous work, was conducted for inducing AGG and a bamboo-like microstructure, respectively. Optical and electron microscopy were carried out to characterize the prevailing microstructure upon cyclic heat treatment. For characterization of the functional properties following AGG, a load increase test was conducted. The current results clearly show that good shape memory response can be obtained in Fe–Mn–Al–Ni SMA upon EB welding and subsequent post-heat treatment. These results further substantiate the potential use of conventional processing routes for Fe–Mn–Al–Ni SMA.

Oxidation resistance of TiAl alloy improved by hot-pack rolling and cyclic heat treatment

2021 ◽  
pp. 111196
Author(s):  
Tian Shiwei ◽  
He Anrui ◽  
Liu Jianhua ◽  
Zhang Yefei ◽  
Yang Yonggang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Oxidation Resistance ◽  
Tial Alloy ◽  
Cyclic Heat Treatment ◽  
Pack Rolling ◽  
Cyclic Heat ◽  
Hot Pack

scholarly journals Laser Powder Bed Fusion Processing of Fe-Mn-Al-Ni Shape Memory Alloy—On the Effect of Elevated Platform Temperatures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 185
Author(s):  
Felix Clemens Ewald ◽  
Florian Brenne ◽  
Tobias Gustmann ◽  
Malte Vollmer ◽  
Philipp Krooß ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Crack Formation ◽  
Microstructural Analysis ◽  
Tensile Load ◽  
Grain Structure ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Cyclic Heat Treatment ◽  
Powder Bed ◽  
Cyclic Heat

In order to overcome constraints related to crack formation during additive processing (laser powder bed fusion, L-BPF) of Fe-Mn-Al-Ni, the potential of high-temperature L-PBF processing was investigated in the present study. The effect of the process parameters on crack formation, grain structure, and phase distribution in the as-built condition, as well as in the course of cyclic heat treatment was examined by microstructural analysis. Optimized processing parameters were applied to fabricate cylindrical samples featuring a crack-free and columnar grained microstructure. In the course of cyclic heat treatment, abnormal grain growth (AGG) sets in, eventually promoting the evolution of a bamboo like microstructure. Testing under tensile load revealed a well-defined stress plateau and reversible strains of up to 4%.

Glass-limited Yb/Er:NaLuF4 nanocrystals: reversible hexagonal-to-cubic phase transition and anti-counterfeiting

2020 ◽  
Vol 8 (45) ◽  
pp. 16151-16159
Author(s):  
Shaoxiong Wang ◽  
Jidong Lin ◽  
Xiaoyan Li ◽  
Jiangkun Chen ◽  
Changbin Yang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Heat Treatment ◽  
Hexagonal Phase ◽  
Cubic Phase ◽  
Practical Application ◽  
Cyclic Heat Treatment ◽  
Cyclic Heat ◽  
High Level

Yb/Er:NaLuF4@glass with in situ reversible cubic-to-hexagonal phase transition on cyclic heat-treatment shows practical application in high-level anticounterfeiting.

scholarly journals Thermal Stresses in the Wall Connections of Cast Grate Structures

2016 ◽  
Vol 16 (4) ◽  
pp. 11-16 ◽  
Author(s):  
A. Bajwoluk ◽  
P. Gutowski
Keyword(s):  
Heat Treatment ◽  
Cross Section ◽  
Hot Spots ◽  
Thermal Stresses ◽  
Cooling Process ◽  
Temperature Variations ◽  
Temperature Changes ◽  
Different Types ◽  
The Difference ◽  
The Impact

Abstract The purpose of this study was to establish a relationship between the type of wall connection used in the cast grates, which are part of the equipment operating in furnaces for heat treatment and thermal-chemical treatment, and stresses generated in these grates during the process of rapid cooling. The places where the grate walls are connected to each other are usually characterized by the thickness larger than the remaining parts of walls. Temperature variations in those places are responsible for the formation of hot spots, and in the hot spots temperature changes much more slowly. The type of wall connection shapes the temperature gradient in the joint cross-section, and hence also the value of thermal stresses generated during cooling. In this study, five different designs of the grates were compared; the difference in them was the type of the designed wall connection. The following design variants were adopted in the studies: X connections with and without holes, T connections with and without technological recesses, and R (ring) connection. Numerical analysis was performed to examine how the distribution of temperature changes in the initial phases of the cooling process. The obtained results served next as a tool in studies of the stress distribution in individual structures. The analysis were carried out by FEM in Midas NFX 2014 software. Based on the results obtained, the conclusions were drawn about the impact of different types of wall connections on the formation of thermal stresses in cast grates.

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