Assisting Liquid Phase Sintering of Pure Aluminum (Al) by the Tin Addition

In the present study, the addition of tin (Sn) to the pure Al system was done, and its effects on the morphology, density, and compressive yield strength of pure Al were analyzed systematically. In this context, the morphology of sintered Al revealed enhanced wettability and sintering response between Al particles with increased Sn content. Moreover, physical characteristics of sintered Al alloys demonstrated oxidation phenomenon (black color specimen) with the lowest Sn content of 1.5 weight percent (wt.%), in which a higher Sn content of 2 and 2.5 wt.% produced silver color specimens, implying a reduction in oxidation. Additionally, densification of sintered Al alloys was greatly promoted with increased Sn contents, suggesting effective wetting as confirmed by the previous morphological observations. Similarly, the compressive yield strength of sintered Al alloys improved with increased Sn content which might be due to the enhanced inter-particle contacts between Al particles and sufficient wetting by molten Sn. Based on the results obtained, the introduction of Sn powder at various contents improved the sintering response of pure Al powder by providing sufficient liquid-phase sintering. Therefore, the sintered Al alloys had enhanced the morphological, densification, physical characteristics, and compressive yield strength.

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Structural, Physical and Mechanical Properties of Mg-Al Alloys Processed under CO2 Atmosphere

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.545.247 ◽

2012 ◽

Vol 545 ◽

pp. 247-250 ◽

Cited By ~ 1

Author(s):

Subramanian Jayalakshmi ◽

Khoo Chee Guan ◽

Kuma Joshua ◽

Manoj Gupta

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Yield Strength ◽

Magnesium Alloys ◽

Physical And Mechanical Properties ◽

Melting Process ◽

Al Alloys ◽

Compressive Yield Strength ◽

Protective Atmospheres

Magnesium alloys are the lightest structural materials known that are increasingly replacing steel and aluminium. However, due to its flammable nature, protective atmospheres are employed during Mg-alloy production. In this novel work, Mg-Al alloys with ~3 and ~5 wt.% Al were processed in CO2atmosphere, so as to utilize the CO2during the melting process. The cast Mg-Al alloys were extruded and studied for their structural, physical and mechanical properties. Results showed improvements in mechanical properties such as hardness, tensile strength and compressive yield strength. The improvement in properties was attributed to thein situformation of Al4C3arising due to molten metal-carbon interaction. It is noteworthy that the incorporation of CO2during processing did not adversely affect the mechanical properties of the alloys. Further, the process is eco-friendly as it not only utilized CO2, but also eliminates use of harmful cover gases.

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Mechanical Properties Variation with Test Temperature for Liquid Phase Sintered 95W-3.5Ni-1.5Fe Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.647 ◽

2007 ◽

Vol 561-565 ◽

pp. 647-650 ◽

Cited By ~ 1

Author(s):

Syed Humail Islam ◽

M. Tufail ◽

Xuan Hui Qu

Keyword(s):

Mechanical Properties ◽

Liquid Phase ◽

Yield Strength ◽

Room Temperature ◽

Substantial Reduction ◽

Testing Temperature ◽

Liquid Phase Sintering ◽

Transgranular Fracture ◽

Dual Phase ◽

High Temperature Mechanical Properties

The high temperature mechanical properties of dual phase heavy metal of 95W-3.5Ni-1.5Fe alloy were investigated in tension. The specimens were prepared by liquid phase sintering. Yield strength decreased and ductility increased as the testing temperature was increased to 300°C, reached a plateau at between 300 and 500°C and then decreased considerably. The fracture modes of alloys when deformed at room temperature were a mixture of intergranular fracture and transgranular cleavage. As the temperature was increased, the percentage of intergranular cleavage increased, although transgranular fracture also remained. At higher temperatures, substantial reduction in ductility and in yield strength was a result of loss of bonding strength between tungsten grains and matrix phase.

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Effect of Interfacial Layers on the Performance of Cu-In Liquid Phase Sintered Composites as Thermal Interface and Interconnect Materials

ASME 2011 Pacific Rim Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Systems, MEMS and NEMS: Volume 2 ◽

10.1115/ipack2011-52221 ◽

2011 ◽

Author(s):

J. Liu ◽

P. Kumar ◽

I. Dutta ◽

C. M. Nagaraj ◽

R. Raj ◽

...

Keyword(s):

Liquid Phase ◽

Yield Strength ◽

Interfacial Layer ◽

Volume Fraction ◽

Liquid Phase Sintering ◽

Thermal Interface ◽

Interfacial Layers ◽

Electrical Conductivities ◽

Long Term Performance ◽

Term Performance

In this study, a novel architecture composed of uniformly distributed high melting phase (HMP, e.g. Cu) in a low melting phase (LMP, e.g. In) matrix, which can be produced via liquid phase sintering (LPS), is proposed to produce next generation thermal interface materials (TIMs) and interconnect (IC) materials. The LMP determines the shear compliance of these composites whereas the HMP determines its thermal and electrical conductivities. The volume fraction of In was optimized to produce a Cu-In solder with suitable mechanical, electrical and thermal properties for TIM and IC applications. Since, Cu and In react to form several Cu-In intermetallic compounds (IMCs), which may deteriorate the long-term performance of these solders, interfacial-layers of Au and Al2O3 were applied on Cu to further improve the performance of the Cu-In solders. The effect of interfacial-layers on the reaction between Cu and In, during sintering at 160°C and during aging at 125°C, was studied and its impact on the mechanical, thermal and electrical properties was evaluated. Au interfacial layer (50∼200nm) quickly reacted with In to form AuIn2 IMC, which acted as a tenacious diffusion-barrier and slowed down the reactions between Cu and In. 8-monolayer thick Al2O3 did not react with either Cu or In and inhibited reactions between Cu and In. During short-time sintering, the effect of interfacial layer on the thicknesses of IMCs was insignificant to affect the yield strength of the as-sintered composites. However, IMC layer thickened rapidly in the Cu-In composites without an interfacial-layer, which led to a drastic decrease in the volume fraction of unreacted In leading to an increase in the yield strength of the solder. On the other hand, the interfacial-layers effectively suppressed the growth of IMCs during aging and hence the yield strength of such composites increased at slower rates. Since, the IMCs formed at the interface radically affect the contact resistance, significant differences in the thermal and electrical conductivities were recorded for the solders with different interfacial-layers.

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Effect of Zn and Zr Concentration and Extrusion Conditions on the Mechanical Properties of Lean ZK Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.828-829.279 ◽

2015 ◽

Vol 828-829 ◽

pp. 279-284

Author(s):

N.G. Ross ◽

A. Elrefaey ◽

Richard Kretz ◽

Helmut Kilian

Keyword(s):

Mechanical Properties ◽

Yield Strength ◽

Element Concentration ◽

Weight Percent ◽

Al Alloys ◽

Mg Alloys ◽

Minor Effect ◽

Alloying Element ◽

Extrusion Speed ◽

A Minor

Compared to Al alloys Mg alloys are generally slower to extrude and this makes them expensive to process. However, making alloys easier to extrude usually equates to reduced extrudate strength. The effects of extrusion parameter, billet heat treatments and alloying element concentration on extrudability and extrudate mechanical properties are compared using four lean ZK alloys. By weight percent there was a greater increase in peak extrusion pressure and extrudate yield strength from increasing Zr than from Zn. Homogenising the extrusion billets had no effect on the lean alloys and only a minor effect on the richer alloys. Alloying element concentration has the most effect on alloy mechanical properties, while changing the extrusion speed and temperature has little influence on the extrudate mechanical properties.

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MACROSTRUCTURE AND STRENGTH OF AL–ZN–SN COMPOSITE PRODUCED BY LIQUID PHASE SINTERING OF AL–ZN ALLOY AND PURE TIN POWDER MIXTURE

Izvestiya Vuzov Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Universitiesʹ Proceedings Powder Metallurgy аnd Functional Coatings) ◽

10.17073/1997-308x-2018-2-69-75 ◽

2018 ◽

pp. 69-75

Author(s):

N. M. Rusin ◽

A. L. Skorentsev

Keyword(s):

Liquid Phase ◽

Powder Mixture ◽

Sintering Temperature ◽

Pure Aluminum ◽

Aluminum Matrix ◽

Liquid Phase Sintering ◽

Holding Time ◽

Vacuum Furnace ◽

Residual Pressure ◽

Localized Deformation

The paper studies the liquid phase sintering features of compacts made of Al–10Zn alloy and Grade PO 2 tin powder mixture as well as the effect of sintering modes on the structure and strength of the (Al–10Zn)–40Sn antifriction composite formed. The porosity of original raw compacts ranged from 5 to 18 %. They were sintered in a vacuum furnace at a residual pressure of gases lower than 10–2 MPa. Sintering temperature varied from 550 to 615 °С, where partial aluminum wetting with liquid tin was observed. Sample holding time at a given sintering temperature was 30–180 min. Structural studies have shown that the particle size of aluminum and tin phases increased with an increase in sintering temperature and holding time. Mechanical properties of sintered composites were determined by the compression test. Test samples were cut from the middle area of sintered compacts. The tests have shown that (Al–10Zn)–40Sn composite samples have high ductility. Moreover, these samples exhibit higher strength in comparison with Al–40Sn sintered composite with a pure aluminum matrix due to more intensive strain hardening of the matrix at high deformation levels. It was found that the composites obtained when sintering samples with a low initial porosity and subjected to pre-exposure at low temperature have the highest strength. Based on the reported results it can be concluded that the liquid-phase sintering method within the specified temperature range allows to obtain the (Al–10Zn)–40Sn composites with a continuous aluminum matrix to effectively prevent localized deformation in the soft Sn interlayers. The optimum sintering temperature should not exceed 600 °С.

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Effect of furnace atmosphere and silica content on the consolidation behaviour of magnesia partially stabilised zirconia

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178410 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1056-1057

Author(s):

J. Drennan ◽

R.H.J. Hannink ◽

D.R. Clarke ◽

T.M. Shaw

Keyword(s):

Liquid Phase ◽

Silica Content ◽

Liquid Phase Sintering ◽

Furnace Atmosphere ◽

Boundary Phase ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Series Of Experiments ◽

Compositional Gradients ◽

Mobile Liquid

Magnesia partially stabilised zirconia (Mg-PSZ) ceramics are renowned for their excellent nechanical properties. These are effected by processing conditions and purity of starting materials. It has been previously shown that small additions of strontia (SrO) have the effect of removing the major contaminant, silica (SiO2).The mechanism by which this occurs is not fully understood but the strontia appears to form a very mobile liquid phase at the grain boundaries. As the sintering reaches the final stages the liquid phase is expelled to the surface of the ceramic. A series of experiments, to examine the behaviour of the liquid grain boundary phase, were designed to produce compositional gradients across the ceramic bodies. To achieve this, changes in both silica content and furnace atmosphere were implemented. Analytical electron microscope techniques were used to monitor the form and composition of the phases developed. This paper describes the results of our investigation and the presentation will discuss the work with reference to liquid phase sintering of ceramics in general.

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Microstructure and microanalysis of sintered Fe-Nd-B permanent magnets

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178082 ◽

1990 ◽

Vol 48 (4) ◽

pp. 990-991

Author(s):

Mahesh Chandramouli

Keyword(s):

Electron Microscope ◽

Liquid Phase ◽

Permanent Magnets ◽

Phase Distribution ◽

Energy Dispersive Spectrometer ◽

Nucleation And Growth ◽

Liquid Phase Sintering ◽

Domain Wall Energy ◽

Oxide Phases ◽

Scanning Electron

Magnetization reversal in sintered Fe-Nd-B, a complex, multiphase material, occurs by nucleation and growth of reverse domains making the isolation of the ferromagnetic Fe14Nd2B grains by other nonmagnetic phases crucial. The magnets used in this study were slightly rich in Nd (in comparison to Fe14Nd2B) to promote the formation of Nd-oxides at multigrain junctions and incorporated Dy80Al20 as a liquid phase sintering addition. Dy has been shown to increase the domain wall energy thus making nucleation more difficult while Al is thought to improve the wettability of the Nd-oxide phases.Bulk polished samples were examined in a JEOL 35CF scanning electron microscope (SEM) operated at 30keV equipped with a Be window energy dispersive spectrometer (EDS) detector in order to determine the phase distribution.

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