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In this investigation the surface of an aluminized sample of plain carbon steel was melted and alloyed using a tingsten inert gas (TIG) welding process to produce iron-aluminide intermetallic phases on the surface. The produced coating was then characterized by SEM and EDS and its high-temperature properties in O2+ 1% SO2 gas were examined. The results showed that the Fe3Al coating produced could protect the substrate as it was subjected to the corroding gases at 700oC due to the formation of an alumina layer between the substrate and an outer layer of Fe2O3. At 900oC, the coating could only protect the substrate for 64 h. The lack of further protection at this temperature is attributed to the decrease in the protective properties of alumin
Electromagnetic stir casting process of A357−SiC nanocomposite was discussed using the D-optimal design of experiment (DODOE) method. As the main objective, nine random experiments obtained by DX-7 software were performed. By this method, A357−SiC nanocomposites with 0.5, 1.0 and 1.5 wt.% SiC were fabricated at three different frequencies (10, 35 and 60 Hz) in the experimental stage. The microstructural evolution was characterized by scanning electron and optical microscopes, and the mechanical properties were investigated using hardness and room- temperature uniaxial tensile tests. The results showed that the homogeneous distribution of SiC nanoparticles leads to the microstructure evolution from dendritic to non-dendritic form and a r
Herein, the evolution of the microstructure of a newly developed oxide dispersion strengthened (ODS) Ni‐based superalloy with emphasis on γ′ morphology during different processing conditions is investigated. X‐ray analysis of severely deformed mechanically alloyed (MAed) powders shows that the as‐milled nano‐sized crystallite size increases with annealing associated with the sharp drop of dislocation density. At the same time, by annealing MAed powders γ′ precipitates above 300 ?C, and depending on the aging treatment regime, Vickers microhardness changes mainly due to γ′ distribution and dislocation release. The thorough evaluation of γ′ morphology in the microscale shows that in contrast to the spherical shape of γ
The present study investigates the effects of adding 2.5 wt,% of chromium on the phase transformation, microstructure, and mechanical properties of an advanced medium-manganese high-strength steel containing 4.5 wt.% of manganese. The addition of chromium enhanced the hardenability and a fully martensitic structure formed after the hot-rolling process and air-cooling the rolled sheet and consequently austenitization and rapid cooling which are part of the production route of medium-manganese steel sheets was eliminated. Also, the addition of chromium made it possible to choose higher annealing temperatures because of transforming the carbide phases into carbides stable at higher temperatures. The investigation of the microstructure, phases,
Zr-based bulk metallic glasses (BMGs) offer a noticeable potential for engineering applications because of their good mechanical properties. Annealing plays an important role in changing the mechanical properties of these materials, especially the hardness and ductility. However, the effects of annealing on the tribological behavior of the BMGs are still inexplicit. In the present study, the wear behavior of the as-cast and different annealed states of Zr60Cu10Al15Ni15 BMG, i.e., sliding against AISI 52100 steel, was evaluated by the pin-on-disc measurement technique. The results indicate that the coefficient of friction varies from 0.39 to 0.63. The relaxed sample had the lowest wear rate, while the hardness of the partially and fully crys
The effect of hot rolling and austenite revert transformation (ART) on the microstructure development and mechanical properties for a series of newly developed manganese steels with small carbon and/or boron content was investigated in this study. The cast steels were hot rolled, ART annealed and subjected to tensile testings after each step. The carbon-bearing alloy revealed a significant combination of ultimate tensile strength (UTS) and elongation (El.?pct) with 1.1?GPa and 42?pct values, respectively. The boron-bearing alloy exhibited a UTS of 760?MPa having 30?pct elongation. Moreover, the carbon and boron alloyed steel had a fully martensitic structure with a UTS of 1.4?GPa and a negligible elongation. X-ray diffraction,
Here, hardenability was enhanced by choosing two different chemical compositions, i.e. the addition of boron (0.12 wt-%) and chromium (2.5 wt-%) to the ordinary composition of the medium Mn advanced high-strength steels (AHSSs). Carbo-boride precipitates were formed in the samples having both boron and carbon in their compositions. Martensite was tempered after intercritical annealing at 700?C. In the alloy with both boron and carbon (A2 alloy), austenite was formed by 2.8 vol.-% after 10-min annealing. Primarily, the annealing process led to the austenite stabilization in the structure of the cold-rolled A2 alloy due to the dissolution of carbo-boride precipitates. For the carbon-free alloy (A1 alloy), on the other, the annealing pro
In this study, flux-cored arc welding was performed to deposit an Fe-based super-hard hardfacing whit 911 HV30 on an st37 substrate. The dry sand/rubber wheel abrasion test (ASTM G65) was performed to investigate the abrasive wear behavior of the hardfacing deposit and its average weight loss was measured to be 0.075 gr. The worn surface and cross sections of wear sample were studied by optical microscopy and scanning electron microscopy. The results showed that the fracture behavior of the phases during abrasion testing is similar to their fracture behavior during macro-indentation fracture toughness testing investigated in the previous study (Bahoosh et al. in Eng Fail Anal 92:480–494, https://doi.org/1
A method for producing alloy steel is provided. An alloy mixture may be melted to produce a melted alloy mixture. The alloy mixture comprises 2 to 4 weight% chromium (Cr), 12 to 16 weight% manganese (Mn), at most 4 weight% silicone (Si), 1 to 3 weight% aluminum (Al), at most 0.3 weight% carbon (C) and iron (Fe). The melted alloy mixture may be formed into a product. The product may be heated to produce a thermally homogenized product. The thermally homogenized product may be hot rolled into a plate with a first thickness. The plate may be warm rolled at a warm rolling temperature until the plate has a second thickness. The warm rolling temperature may be configured such that a crystal structure of the plate has 30 to 70 volume% austenite. T
Recently, wear resistant properties of metallic glasses has attracted a lot of interest. Because the surface of metallic glasses are prone to phase transformation, finding the effects of test condition on structure and wear behavior of metallic glasses is important. In this research, by using an automated electrospark deposition (ESD), a layer of Fe51Cr18Mo7B16C4Nb4 was deposited on AISI 3161 stainless steel. Metallographic, scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS) analyses of the coating were conducted for measuring the thickness and analyzing composition of the coating. X-ray diffraction (XRD), Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) investigations show
A super-hard hardfacing Fe-based electrode with 911 HV30 was applied to st37 substrate using flux-cored arc welding method. Microstructural study was accomplished using X-ray diffraction, scanning electron microscope and microscopic image analysis software. The fracture toughness properties of the phases were examined using the macro-indentation fracture toughness method. In the fracture toughness test, Palmqvist cracking mode was observed and the fracture toughness of the hardfacing steel was calculated to be 23.1 MPa√m. Furthermore, preferential crack growth direction, crack growth steps and the fracture behavior of the phases were determined using scanning electron microscope images.
The work-hardening mechanisms of two novel advanced high-strength steels (Fe67.4−xCr15.5Ni14.1Si3.0Bx [x = 0 (0B), 2 (2B)] wt%) were investigated by means of field emission gun scanning electron microscopy coupled with angle-selective backscattered detection, transmission electron microscopy, and electron backscattered diffraction. The 0B and 2B specimens combined low yield stresses and high ultimate tensile strengths with good total elongation percentages, with results of 219?MPa, 568?MPa, and 83% and 357?MPa, 703?MPa, and 42%, respectively. The 0B and 2B alloys were characterized by a decreasing work hardening rate, followed by a constant and finally a steep decreasing change tendency. Detailed angle-selective backscattered and electron
In this research, the effects of electromagnetic stirring and 1.5?wt% SiC nanoparticles on the solidification microstructure and mechanical properties of alloy Al A357 were studied at three different frequencies (10, 35, and 60?Hz). The microstructural evolution was characterized by scanning electron and optical microscopy, and the mechanical properties were studied by hardness and room-temperature uniaxial tensile tests. The results showed that with an increase in frequency to 60?Hz in the presence of 1.5?wt% SiC nanoparticles, the dendrite size was reduced from 59.5???1.8 to 15.5???3.6??m (%73.9). By the application of electromagnetic stirrer frequencies from 0 to 60?Hz in the presence of 1.5?wt% SiC nanoparticles, the hard
A tungsten inert gas (TIG) welding process was utilized successfully to produce a dense and hard iron aluminide coating on an aluminized plain carbon steel substrate. The aluminized surface of the steel sheets was melted using different currents in the range of 30 to 50?A. The surface and cross section of the alloyed layers were studied using optical microscopy, scanning electron microscopy, X-ray diffraction and a nano-hardness test. The results showed that the volume of the pool formed during the surface melting had a critical influence on the phases formed during the process. Forty amperes was found to be the optimum TIG current, at which a Fe-rich aluminide consisting mainly of Fe3Al formed on the steel substrate.
An iron based glassy alloy with the nominal stoichiometry of Fe49Cr18Mo7B16C4Nb6 was deposited on a carbon steel substrate by gas tungsten arc welding (GTAW) process. Effects of the number of weld layers and weld heat input were studied. Optical microscope (OM), scanning electron microscope (FE_SEM) and X-ray diffraction analysis (XRD) were used to characterize the microstructure and phase distribution. Hardness and wear behavior of the deposited layers were also investigated. The results showed that a multi-phase structure consisting of hard boride (Mo2FeB2) and nano-sized carbide (NbC) phases were formed in a nanostructured α-Fe matrix. The ratio of hard phases and subsequently hardness of layers were increased by increasing the number o