High entropy INTERMETALLIC COMPOUNDS (HEICs) are an interesting class of materials combining the properties of multicomponent solid solutions and the ordered superlattices in a single material. In this work, microstructural and magnetic properties of (CoCuFeMnNi)Al, (CoCuFeMnNi)Zn3, (FeCoMnNiCr)3Sn2, (FeCoNiMn)3Sn2 and Cu3(InSnSbGaGe) HEICs fabricated by induction melting are studied. The magnetic properties of the HEICs was determined mainly by the nature of the magnetic momentum of the constituent elements. (CoCuFeMnNi)Al and (CoCuFeMnNi)Zn3 displayed ferromagnetic behavior at 5 K, while indicated linear dependency of magnetization vs. magnetic (i.e. paramagnetic or antiferromagnetic state) at 300 K. The magnetization of (FeCoMnNiCr)3Sn2, (FeCoNiMn)3Sn2 and Cu3(InSnSbGaGe) HEICs at 300 K exhibited a nearly linear dependency to magnetic field. Among all the investigated samples, (CoCuFeMnNi)Al exhibited the best magnetic properties with a saturation magnetization of about Ms = 6.5 emu/g and a coercivity of about Hc = 100 Oe.

Combustion synthesis is a special thermophysico-chemical process applied for production of INTERMETALLIC COMPOUNDS. In the present work, a reaction–diffusion numerical model was developed to analyze the combustion synthesis of aluminide INTERMETALLICs by self-propagating high-temperature synthesis process. In order to verify the reliability of the numerical model, an experimental setup was designed and used to perform the combustion synthesis of nickel and titanium aluminides. The developed model was further used to determine the temperature history of a powder mixture compact during self-propagating high-temperature synthesis. The effect of compact relative density on combustion temperature and wave propagation velocity was also studied.

Based on the crystal and magnetic structural properties of some Gd INTERMETALLIC COMPOUNDS, it is shown that with increasing conduction electron concentration, Gd experiences electronic and magnetic instability, and that these behaviors point to the appearance of Kondo Lattice. We suggest that the conduction electrons have gained local character. It is shown that Kondo effect should be observed at around x=0.4. Resistivity studies confirm the calculations, and a Kondo temperature of around 70 K found for Gd2Au0.4Al0.6.

Influence of the partial substitution of Co for Fe on the structural, magnetic and magnetoelastic properties of Nd6Fe13Cu COMPOUNDS are investigated. Analysis of X-ray diffraction patterns indicates that the multi-phase sample is formed for all samples. Upon Co substitution, the second phase Nd2Fe17, Nd2Fe17-yCoy with 0<y<1 and Nd2Fe17-zCoz with 1<z<2 is formed in the samples with x=0, 1, 2, respectively so that the lattice parameters are decreased and the Curie temperature is increased. Due to the ferromagnetic phase Nd2Fe17-yCoy in sample with x=1, the change of the anisotropy and increase of exchange effects are observed. The effects of long-range magnetic ordering processes on Néel temperature clearly appear in the temperature dependence of the spontaneous magnetostriction. Longitudinal (ll) and transverse (lt) magnetostrictions are measured to study the magnetoelastic behaviour of these COMPOUNDS using a strain gauge method. In the low field region, magnetostrictive strains are small and then increase with increasing fields. Strong pining center of Nd atoms that creates large magnetocrystalline anisotropy prevents easy movement of domain walls. In the sample with x=0, the magnetostriction contribution from the rare earth sublattice (Nd) dominates at low temperature and the Fe sublattice contribution becomes increasingly important as temperature rises.

In this study, by mechanical alloying method with a powerful bullet milling machine (SPEX) was used to create aluminum coating on the simple carbon steel surface (Ck 45) Balls with diameter of 4mm with a total weight of 50g and 5g aluminum powder with 99. 99% purity, the size of smaller particles than 150μ m and weight of 5g with (Ck 45) steel specimen were 8×8 mm with a thickness of 3mm were put into the milling chamber and milled for different times from 10min to 30h at room temperature. As-milled samples were annealed at 550˚ C at different times (2, 4, 6, 8, 10, 30h) to evaluate the formation of Fe-Al INTERMETALLIC COMPOUNDS, and the effect of thermal treatment coating properties such as: adhesion rate, fuzzy changes thickness of INTERMETALLIC COMPOUNDS surface were investigated. Structures of the produced coating were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), spectrometry and micro hardness test. The results showed that the best coating in terms of micro structural properties and uniformity was created after 80 min ball milling. The results of the thermal treatment at a constant temperature of 550˚ C for 30h showed that the interface between the aluminum coating and the steel substrate is formed and has a thickness of 28 micrometer. Furthermore the micro hardness test was carried out on the coated samples and results showed that the coating after the 80 min alloying, before thermal treatment had a low hardness of about 75 Vickers after performing the thermal treatment for 30h, the hardness of coverage in the interface of Fe/Al was increased to 471 Vickers.

In this article, an attempt was made to investigate the effect of the addition of silicon on the titanium aluminide compound formation from TiO2 and Al raw materials. Silicon has a eutectic with aluminum and can reduce its melting temperature, which can have effective impact on the formation of titanium aluminide COMPOUNDS. On the other hand, due to the production of Ti5Si3 compound, it can be effective in increasing the oxidation resistance of COMPOUNDS and composites containing titanium aluminide. With this aim in mind, the present paper has strove to determine the impact of this element on the formation of titanium aluminides and the type of titanium silicide phases by adding different amounts of silicon to TiO2 and Al raw materials. The key findings emerged, showed that when silicon is added to the system in small amounts (0.1), it not only does not have a positive effect on the reactions, it also prevents the formation of titanium aluminide COMPOUNDS, but with an increase in its percentage (0.28), it also causes the formation of these titanium aluminide COMPOUNDS and leads to the formation of Ti5Si3 phase. This phase changes from a discrete morphology to a continuous state as the percentage of silicon increases (0.6). With a further increase in the amount of silicon (1), the TiSi2 phase is formed, which is dispersed throughout the sample with a string-like structure.

The aim of the present study is to investigate the effect of Al-Fe INTERMETALLIC COMPOUNDS on the strength of friction stir spot welded (FSSW) joints. The tool rotational speed and dwell time were the studied process parameters. The microstructure of the joint interface was characterized using optical and scanning electron microscopes. Tensile-shear testing results showed that the strength of the welds improved with the enhancement of dwell time for all of the applied rotational speeds. Furthermore, for a given dwell time, higher rotational speeds led to stronger joints. Microstructural observations revealed that the strength of the welds increased with the growth of the INTERMETALLIC layer thickness up to 5 mm.

Titanium aluminides have received much attention due to their suitable properties such as lightness, maintaining strength at high temperatures, and resistance to corrosion and oxidation. Therefore, titanium aluminides and their composite play a key role in the industry, especially in urban transportation and aviation industries. The melting of aluminum is recognized as the first step of the titanium aluminide formation process from elemental powders or raw materials of TiO2 and Al. Facilitating the aluminum smelting could be a contributing factor to accelerating the titanium aluminide-generating procedure. Selecting copper as an agent to reduce the melting point of aluminum is based on the binary phase diagram of Al-Cu in which a eutectic transformation is obvious. Different molar ratios of copper were added to the raw materials of aluminum and titania. Then the resulting compressed powder samples were subjected to heat treatment. It was found that up to a certain molar ratio, copper could reduce aluminum's melting temperature and promote the formation of titanium aluminide INTERMETALLIC COMPOUNDS. The optimal amount of copper (0.2) has also greatly contributed to the uniformity and homogeneity of the composite structure. In general, in this research, the effect of copper on the production of titanium aluminide has been discussed both theoretically and practically.

In the present study, the effect of post-rolling annealing heat treatment on the formation of INTERMETALLIC COMPOUNDS between Al-Cu strips, in the presence of nickel coating on the Cu strips, was investigated. In addition, the effect of post-rolling annealing and INTERMETALLIC COMPOUNDS on the bond strength of Al-Cu strips was evaluated. In order to prepare samples, Cu strips were coated with nickel by electroplating process. After surface preparing, Cu strips were placed between two Al strips and roll bonded. This method is used for producing Al-Ni-Cu composites. Then the samples were annealed at 773K for 2 h. The formation of INTERMETALLIC COMPOUNDS was studied using energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Also, in order to investigate bond strength of Al-Cu after post-rolling annealing heat treatment, samples were produced using nickel powder and nickel coating. Then bond strength of strips was investigated using peeling test. The results revealed that by post-rolling annealing of layers, the bond strength between Al-Cu strips decreases dramatically.