The fluid surface shape and capillary phenomena under lowered gravity or weightlessness with application to space materials science (powder metallurgy technology: impregnation, liquid-phase sintering; welding, brazing)

2004 ◽  
Vol 10 (2-3) ◽  
pp. 59-67
Author(s):  
Yu.V. Naidich ◽  
◽  
I.I. Gab ◽  
V.A. Evdokimov ◽  
D.I. Kurkova ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Liquid Phase ◽  
Materials Science ◽  
Liquid Phase Sintering ◽  
Surface Shape ◽  
Fluid Surface ◽  
Capillary Phenomena

Mechanical properties of Al-Cu/B4C and Al-Mg/B4C metal matrix composites

2021 ◽  
Vol 63 (4) ◽  
pp. 350-355
Author(s):  
Mehmet Ayvaz ◽  
Hakan Cetinel
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Liquid Phase ◽  
Oxide Layer ◽  
Solid Phase ◽  
Aluminum Matrix ◽  
Liquid Phase Sintering ◽  
Aluminum Matrix Composites ◽  
Powder Metallurgy Method ◽  
Matrix Composites

Abstract To be able to successfully produce ceramic-reinforced aluminum matrix composites by using the powder metallurgy method, the wetting of ceramic reinforcements should be increased. In addition, the negative effects of the oxide layer of the aluminum matrix on sinterability should be minimized. In order to break the oxide layer, the deoxidation property of Mg can be used. Furthermore, by creating a liquid phase, both wettability and sinterability can be improved. In this study, the effects of Mg and Cu alloy elements and sintering phase on the wettability, sinterability, and mechanical properties of Al/B4C composites were investigated. For this purpose, various amounts (5, 10, 20, and 30 wt.-%) of B4C reinforced Al5Cu and Al5Mg matrix composites were produced by the powder metallurgy method. After pressing under 400 MPa pressure, composite samples were sintered for 4 hours. The sintering was carried out in two different groups as solid phase sintering at 560 °C and liquid phase sintering at 610 °C. Despite the deoxidation effect of Mg in Al5Mg matrix composites, higher mechanical properties were determined in Al5Cu composites which were sintered in liquid phase because wettability increased. The highest mechanical properties were obtained in the 20 wt.-% B4C reinforced Al5Cu sample sintered in liquid phase.

The Use of Transient Liquid Phases in Powder Metallurgy

2021 ◽  
Vol 1016 ◽  
pp. 69-76
Author(s):  
Herbert Danninger ◽  
Raquel de Oro Calderon ◽  
Christian Gierl-Mayer
Keyword(s):  
Powder Metallurgy ◽  
Liquid Phase ◽  
Transient Liquid Phase ◽  
Liquid Phase Sintering ◽  
Porous Powder ◽  
Material Transport ◽  
Liquid Phases ◽  
Short Period ◽  
Constant Quantity ◽  
Transient Liquid Phases

Liquid phase sintering is most widely known in its variant „persistent liquid phase sintering“, in which case the liquid phase is present in constant quantity during the entire isothermal period. There is however also the variant „transient liquid phase“, the melt being present only for a short period in the first stage of sintering and then solidifying through diffusional processes. In this presentation, the preconditions for both variants are presented, in particular with regard to the starting materials. The benefits of transient liquid phases are described, both for sintering – to accelerate material transport, contact formation and microstructural homogenization compared to standard solid state sintering – and for transient liquid phase bonding, a brazing variant which is an attractive method for joining porous powder compacts. Both techniques are highly useful in particular for ferrous powder metallurgy precision components, etc.

Effect of Compacting Pressure on Liquid Phase Sintering of ASTM 2124 Alloy

2010 ◽  
Vol 660-661 ◽  
pp. 623-628 ◽  
Author(s):  
Luzinete Pereira Barbosa ◽  
E.P.R. Lima ◽  
Daniel Rodrigues ◽  
F. Ambrozio Filho
Keyword(s):  
Powder Metallurgy ◽  
Liquid Phase ◽  
Automobile Industry ◽  
Alloy Powder ◽  
Compaction Pressure ◽  
Liquid Phase Sintering ◽  
Scanning Calorimetry ◽  
Sintered Aluminum ◽  
Compacting Pressure

The use of pressed and sintered aluminum, obtained by the powder metallurgy route, to produce large quantities of near-net-shaped components is increasing rapidly in the automobile industry. The production of lightweight pieces of Al by powder metallurgy has attracted increasing attention due to its unique properties. Sintering helps develop mechanical strength and other properties in commercial alloys obtained by powder metallurgy. Sintering of Al can be achieved only upon formation of a liquid phase capable of destroying the extremely stable oxide layer on the surface of the Al particles. The aim of this investigation was to analyze the effect of compaction pressure on sintering of atomized ASTM 2124 type alloy. Powder characterization was carried out using scanning electron microscopy (SEM). The specimens were axially compacted at pressures of 500, 600 and 700 MPa. Differential scanning calorimetry (DSC) was carried out to determine the sintering temperature of the alloy powder. The specimens were sintered at 570° C. Characterization of the sintered material consisted of density measurements and optical as well as SEM examinations. Nevertheless, even the low recycling cost of Al , what increases its useful time and stabilizes its value, the large amount of energy required to obtain it reduce its application.

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