• Tribology and Lubricants
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• v.34 no.2
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• pp.67-73
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• 2018

Ni-Al intermetallic coating technology is an available method for the strengthening of aluminum substrate. In this study, Ni-Al intermetallics were coated on an aluminum substrate through a reaction synthesis process at a temperature lower than melting point of aluminum. And the sliding wear properties of the coatings have been investigated to verify their usability and compared the wear properties with those of a cast Al-12.5%Si alloy and an anodizing layer on aluminum. Results show that the wear rate of the coating layer greatly increased at 1 m/s and 1.5 m/s when compared with that of the cast Al-12.5%Si alloy. Much pitting damages were observed on the worn surfaces at these sliding speeds, unlike at other sliding speeds. The wear of the intermetallic coating layer at these sliding speeds seems to be increased by pitting as a consequence of adhesion. In contrast, wear of the coating layer at other speeds hardly occurs, regardless of wear periods. Nevertheless, the wear properties of the intermetallic coating layer on the aluminum substrate through the reaction synthesis process are more stable than those of anodized aluminum and are superior to those of the cast Al-12.5%Si alloy in a steady-state wear period.

• Journal of Korea Foundry Society
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• v.36 no.1
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• pp.24-31
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• 2016

CD4MCU duplex stainless steel with gadolinium was fabricated as a neutron absorbing material by the air induction melting method. The gadolinium formed intermetallic compounds of Cu-Gd-Fe. There were no significant differences in hardness or ultimate tensile strength between experimental alloys. With the addition of gadolinium the yield strength of the cast alloy significantly increased, from $478.8{\pm}11.6$ to $514.2{\pm}29.9MPa$, whereas elongation of the cast alloy decreased with the addition of gadolinium, from $26.0{\pm}7.1$ to $7.0{\pm}2.5%$ due to the formation of gadolinium based intermetallic compounds.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.4
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• pp.190-199
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• 2015

The study is intended to investigate the effect of solution treatment on microstructure and corrosion behavior of AZ91(Mg-9%Al-1%Zn-0.3%Mn)-2%Ca casting alloy. In as-cast state, the AZ91-2%Ca alloy consisted of intermetallic ${\beta}(Mg_{17}Al_{12})$, $Al_8Mn_5$ and $Al_2Ca$ phases in ${\alpha}-(Mg)$ matrix. After the solution treatment, Al within the ${\alpha}-(Mg)$ matrix was distributed more homogeneously, along with the slight decrease in the total amount of intermetallic compounds. The corrosion resistance of the AZ91-2%Ca alloy was improved after the solution treatment. The microstructural examinations for the solution-treated samples revealed that the better corrosion resistance may well be related to the incorporation of more oxides and hydroxides such as $Al_2O_3$, $Al(OH)_3$, CaO and $Ca(OH)_2$ into the surface corrosion product without dissolution of the intermetallic phases along the grain boundaries.

• Journal of Welding and Joining
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• v.25 no.3
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• pp.51-56
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• 2007

A $CO_2$ laser overlay was conducted by using a Fe-based powder on the AC2B aluminum substrate. Cracks and intermetallic compounds (IMC) were observed inconsistently along the interface between the overlay and post-molten layer. A scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) detected some Fe-rich IMC ($Fe_3Al$, FeAl) as well as the brittle Al-rich IMC ($Fe_2Al_5,\;FeAl_3$). Micro vickers hardness proved the formation of Al-rich IMC ($FeAl_3$) along the interface by showing HV0.1 $800{\sim}900$. Furthermore, nano indentation was successfully applied to investigate the behavior of IMC more precisely than the micro vickers hardness.

• Journal of Powder Materials
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• v.6 no.1
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• pp.42-48
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• 1999

Three mixtures of elemental powders of Al-25at.%Ti, 48at.%Ti and 70at.%Ti were offered to ball milling process for the formation of intermetallic compounds of $Al_3Ti$, AlTi and $Ti_3Al$. Ballmilling or attrition process were carried out at the condition of rotaing speed of 110 or 350 rpm at $10^{-3}$ torr vacuum or argon atmospheres. $Al_3Ti$phases were fully obtained by heat treatment for 1 hors at $600^{\circ}C$ with Al-25at.%Ti composition mixtures milled by 100 hours. The amorphous phase was completely formed at the composition of Al-48at.%Ti mixed powders by milling 100hours at the 50 to 1 weight ratio of ball to powder, and AlTi compounds were obtained by heat treament. In the case of Al-70at%Ti mixed powders milled for 100 hours, $Ti_3Al$ and $Al_3Ti$intermetallic compounds were formed by heat treatment for 1 hour at $600^{\circ}C$. By attrition milling of 350rpm for 10 hours, $Ti_3Al$ phase was formed completley after heat treatment for 1 hour at $600^{\circ}C$.

• Journal of Powder Materials
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• v.11 no.2
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• pp.105-110
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• 2004

In this study the possibility to obtain a homogeneous mixture and to produce solid solutions and intermetallic compounds of Fe and Al nano particles by simultaneous pulsed wire evaporation (S-PWE) have been investigated. The Fe and Al wires with 0.45 mm in diameter and 35 mm in length were continuously co-fed by a special mechanism to the explosion chamber and simultaneously exploded. The characteristics, e.g., phase composition, particle shape, and specific surface area of Fe-Al nano powders have been analyzed. The synthesized powders, beside for Al and $\alpha$-Fe, contain significant amount of a high-temperature phase of $\gamma$-Fe, Fe Al and traces of other intermetallics. The phase composition of powders could be changed over broad limits by varying initial explosion conditions, e.g. wire distance, input energy, for parallel wires of different metals. The yield of the nano powder is as large as 40 wt ％ and the powder may include up to 46 wt % FeAl as an intermetallic compound.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.708-711
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• 1999

The Cu/Ni/Au lamellar structure is extensively used as an under bump metallization on silicon file, and on printed circuit board(PCB) pads. Ni is plated Cu by either electroless Ni plating, or electrolytic Ni plating. Unlike the electrolytic Ni plating, the electroless Ni plating does not deposit pure Ni, but a mixture of Ni and phosphorous, because hypophosphite Is used in the chemical reaction for reducing Ni ions. The fracture crack extended at the interface between solder balls of plastic ball grid (PBGA) package and conducting pads of PCB. The fracture is duets to segregation at the interface between Ni$_3$Sn$_4$intermetallic and Ni-P layer. The XPS diffraction results of Cu/Ni/Au results of CU/Ni/AU finishs showed that the Ni was amorphous with supersaturated P. The XPS and EDXA results of the fracture surface indicated that both of the fracture occurred on the transition lesion where Sn, P and Ni concentrations changed.

• Journal of Welding and Joining
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• v.25 no.4
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• pp.72-78
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• 2007

Aluminized steel sheet is a material with excellent heat resistance, thermal reflection and corrosion resistance. It has wide applications, owing to its low cost and excellent performance, in the petrochemical industry, electric power and other energy conversion systems, etc and has attracted the attention of many investigators. But the welding of aluminized steel sheet has a problem of decreasing tensile-shear strength, caused by mixed Al in the weld. This study investigated behavior of Al and its structural properties to resolve this problem. Several analysis equipment(SEM, EDX, EPMA) were used to investigate Al element in the weld. Also microhardness tester and TEM equipment were used to find the intermetallic compound. As a result of this study, Al-rich zones existed in the weld and Fe-Al intermetallic compounds were found in these zones. At the same time, the weldability of aluminized stainless steel sheet was investigated and compared with that of aluminized steel sheet. Although there is a difference between the base metal of the low carbon steel and stainless steel, it is interpreted that a behavior of Al element in the weld is similar.

• Journal of the Korean institute of surface engineering
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• v.27 no.5
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• pp.292-302
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• 1994

Alloy deposits of 80Sn-20Pb, electroplated on Cu-based leadframe alloy from an organic sulfonate bath were aged at $150^{\circ}C$ to form intermetallic phases between substrate and deposit, and effects of the deposit morphology, influenced by deposition conditions, on the fracture resistance of the 80Sn-20Pb deposit aged at $150^{\circ}C$ were examined. The growth rate of intermetallic compound layer on aging depended on the microstructure of deposit ; it was fastest in deposit formed using pulse current in bath without grain refining additive, but slowest in deposit formed using dc current in bath containing grain refining additive in spite of similar structure with equivalent grain size. The grain refining additive incorporated in electrodeposit appears to inhibit diffusion of atoms on aging, resulting in slow growth of intermetallic layer in the thickness direction but substantial growth in the lateral one. Density of surface cracks that were occurring when samples were subjected to the $90^{\circ}$-bending test increased with increasing the thickness of intermatallic layer on aging. For the same aged samples, the surface crack density of the sample electrodeposited from a bath containing the grain refining additive was the least due to the inhibiting effect of the additive incorporated into the deposit during electrolysis on atomic diffusion.

• Korean Journal of Metals and Materials
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• v.48 no.7
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• pp.683-689
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• 2010

In this study, FeAl based intermetallic matrix composites reinforced with in-situ synthesized TiC particles were fabricated by an in-situ liquid mixing process. The microstructures, mechanical properties and fracture behaviors of the in-situ liquid mixing processed composite were investigated and compared with the vacuum suction casting processed composite. The results showed that the in-situ formed TiC particles exhibited fine and uniform dispersion in the liquid mixing processed composite, while significant grain boundary clustering and coarsening of TiC particles were obtained by the vacuum suction process. It was also shown in both types of composites that the hardness and bending strength were increased with the increase of the TiC volume fractions. Through the study of fractography in the bending test, it was considered that the TiC particles prohibited brittle intergranular fracture of FeAl intermetallic matrix by crack deflections. Because of the uniformly distributed fine TiC particles, the bending strength of the liquid mixing processed composite was superior to that of the casting processed composite.