PL
 |
EN
Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 8

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available Effect Of Compaction Pressure And Sintering Temperature On The Liquid Phase Sintering Behavior Of Al-Cu-Zn Alloy
100%
Lee S. H. , Ahn B.
Archives of Metallurgy and Materials
|
2015
|
tom Vol. 60, iss. 2B
1485--1489
EN
The liquid phase sintering characteristics of Al-Cu-Zn alloy were investigated with respect to various powder metallurgy processing conditions. Powders of each alloying elements were blended to form Al-6Cu-5Zn composition and compacted with pressures of 200, 400, and 600 MPa. The sintering process was performed at various temperatures of 410, 560, and 615°C in N2 gas atmosphere. Density and micro-Vickers hardness measurements were conducted at different processing stages, and transverse rupture strength of sintered materials was examined for each condition, respectively. The microstructure was characterized using optical microscope and scanning electron microscopy. The effect of Zn addition on the liquid phase sintering behavior during P/M process of the Al-Cu-Zn alloy was also discussed in detail.
2
Content available High Temperature Deformation Flow Of A ZK60A Magnesium Alloy After Extrusion
80%
Kawasaki M. , Lee H. J. , Oh M. C. , Ahn B.
Archives of Metallurgy and Materials
|
2015
|
tom Vol. 60, iss. 2B
1327--1330
EN
Flow behavior of a ZK60A magnesium alloy after continuous casting and subsequent extrusion was examined in tension at a range of strain rates of 3.0×10-6 − 1.0×10-2 s-1 at temperatures of 473-623K. The results demonstrated that the alloy exhibited a maximum elongation of ~250% at 523K when tested at an initial strain rate of 1.0×10-5 s-1 and strain rate sensitivity, m, of ~0.3-0.4 and the activation energy of ~94 kJ/mol were calculated under the testing conditions. The detailed investigation suggested that the high temperature flow of the ZK60A alloy having submicrometer grains demonstrates quasi-superplastic flow behavior controlled by a dislocation viscous glide process.
3
Content available Microstructural Characterization Of Laser Heat Treated AISI 4140 Steel With Improved Fatigue Behavior
80%
Oh M. C. , Yeom H. , Jeon Y. , Ahn B.
Archives of Metallurgy and Materials
|
2015
|
tom Vol. 60, iss. 2B
1331--1334
EN
The influence of surface heat treatment using laser radiation on the fatigue strength and corresponding microstructural evolution of AISI 4140 alloy steel was investigated in this research. The AISI 4140 alloy steel was radiated by a diode laser to give surface temperatures in the range between 600 and 800°C, and subsequently underwent vibration peening. The fatigue behavior of surface-treated specimens was examined using a giga-cycle ultrasonic fatigue test, and it was compared with that of non-treated and only-peened specimens. Fatigue fractured surfaces and microstructural evolution with respect to the laser treatment temperatures were investigated using an optical microscope. Hardness distribution was measured using Vickers micro-hardness. Higher laser temperature resulted in higher fatigue strength, attributed to the phase transformation.
4
Content available De-Lubrication Behavior Of Novel EBS Based Admixed Lubricant In Aluminum P/M Alloy
80%
Oh M. C. , Seok H. , Kim H. J. , Ahn B.
Archives of Metallurgy and Materials
|
2015
|
tom Vol. 60, iss. 2B
1427--1431
EN
The objective of the present research is to develop a novel lubricant for Al-Cu-Mg P/M alloy and to address the effects of the lubricant and compaction pressure on sintered properties. A lubricant mixture consisting of Ethylene Bis Stearamide, Zn-Stearate, and fatty acid was newly developed in this study, and the de-lubrication behavior was compared with that of other commercial lubricants, such as Ethylene Bis Stearamide, Zn-Stearate, and Al-Stearate. Density and transverse rupture strength of sintered materials with each lubricant were examined, respectively. The microstructural analysis was conducted using optical microscope.
5
Content available Evolution Of Precipitate Morphology During Extrusion In Mg ZK60A Alloy
70%
Park J. , Jung K. H. , Lee G. A. , Kawasaki M. , Ahn B.
Archives of Metallurgy and Materials
|
2015
|
tom Vol. 60, iss. 2B
1423--1426
EN
In this study, a continuously casted ZK60A magnesium alloy (Mg-Zn-Zr) was extruded in two different extrusion ratios, 6:1 and 10:1. The evolution of precipitates was investigated on the two extruded materials and compared with that of as-casted material. The microstructural analysis was performed by electron backscatter diffraction and transmission electron microscopy, and the compositional information was obtained using energy-dispersive X-ray spectroscopy. Several distinct morphologies of precipitates were observed, such as dot, rod, and disk shaped. The formation mechanisms of those precipitates were discussed with respect to the heat and strain during the extrusion process.
6
Content available Understanding the Oxide Dispersion Behavior of Yttria in Metal Matrix of MA956 Alloy through High-Energy Milling and Hot Press Sintering
70%
Swain B. , Han D. , Kim G.-H. , Kong M.-S. , Ahn B.
Archives of Metallurgy and Materials
|
2017
|
tom Vol. 62, iss. 2B
1377--1381
EN
MA956 (Fe-Cr-Al) alloy powder was high-energy ball milled with various amount of yttria contents (1,2,3, and 4 wt.%) to fabricate an oxide dispersion strengthened alloy. The milled powders were then consolidated using hot press sintering at 1150°C. The surface morphology and crystal structure of MA956 powder during the high-energy milling depending on the yttria contents was investigated using particle size analysis, X-ray diffraction, and scanning electron microscopy. The microstructural analysis of sintered alloy was performed using transmission electron microscopy and energy dispersive spectroscopy to evaluate the dispersion behavior of yttrium oxide. The results showed that, as yttria contents increased, the oxide particles became finer and are uniformly distributed during the high-energy milling. However, after the sintering, the oxide particles were coarsened with more than 3 wt.% of yttria addition.
7
Content available Quantitative Analysis of Cryomilled Nanocrystalline Ti-6Al-4V Alloy Powder by X-Ray Diffraction
61%
Oh M. , Yu H. K. , Lee J.-H. , Oh M. C. , Jung S.-H. , Ahn B.
Archives of Metallurgy and Materials
|
2018
|
tom Vol. 63, iss. 3
1439--1442
EN
A nanocrystalline Ti alloy powder was fabricated using cryomilling. The grain size and lattice strain evolution during cryomilling were quantitatively analyzed using X-ray diffraction (XRD) based on the Scherrer equation, Williamson-Hall (W-H) plotting method, and size-strain (S-S) method assuming uniform deformation. Other physical parameters including stress and strain have been calculated. The average crystallite size and the lattice strain evaluated from XRD analysis are in good agreement with the result of transmission electron microscopy (TEM).
8
Content available De-Lubrication Behavior Of Novel EBS Based Admixed Lubricant In Aluminum P/M Alloy
36%
Ahn B. , Oh M. C. , Seok H. , Kim H.-J.
|
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.