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 effect of cooling rate after annealing at 900 °C on the microstructure and hardness of High entropy alloys was investigated using two typical samples with the chemical composition of Co16Cr14.5Fe29Mn11.5Ni29 and Co11.5Cr7Fe27Mn27Ni27(Nb0.08C0.5) (at%). The microstructural characterisation and hardness measurements were carried out by optical microscopy, scanning electron microscopy, wavelength-dispersive X-ray spectroscopy, electron back scattered diffraction, X-ray diffraction technique and Vickers hardness testing. A face centred cubic crystal structure matrix was observed in both alloys before and after annealing and regardless of cooling conditions. SEM analyses revealed an extensive precipitation in Co11.5Cr7Fe27Mn27Ni27(Nb0.08C0.5) alloy after annealing. It was also found that air/furnace cooling can enhance grain growth-coarsening just in Co16Cr14.5Fe29Mn11.5Ni29. However, the hardness results generally showed insignificant hardness variations in both alloys after water-quenching, air-cooling and furnace-cooling. The results suggested that the hardness is mainly controlled by solid solution strengthening.

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.

Nanostructured Zr3Co intennetallic getter compound, due to its High surface area, show enhanced pumping properties and gas sorption response in contrast to the bulk, thin film and commercial getters. Nanostructured Zr3Co intennetallic powders were produced by mechanical alloying (MA) ofthe elemental powders. In the production process, the weight ratio of balls to powder was 1:15 and the rotation speed of planetary ball mill considered as 300rpm After 16 hours of milling, amorphous powder white desired compound was obtained. The phase evolution, microstructural characteristics and formation mechanism of Zr3Co powders during mechanical alloying were studied by means of X- ray diffraction method, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The results showed that after an optimum mechanical alloying time and optimum heat treatment, nanostructured Zr3Co intennetallic powder was achieved. The crystallite grains with sizes of 10 to 20 nm, was achieved respectively. It was found that Zr3Co intennetallic compound is formed by the diffusion of Cobalt into Zirconium during mechanical alloying. In the second stage, after an optimum heat treatment, formation and growth of ZrjCo intennetallic compound are controlled by interdiffusion of Co and Zr.