Journal of Materials Engineering and Performance最新文献

Vanadium carbide (VC)-reinforced Fe-based hard facings are pivotal in enhancing the wear resistance of tools prone to mechanical damage. This study investigates the impact of titanium diboride (TiB₂) addition (at varying laser power and powder federate) on the microstructure, hardness, wear resistance, and corrosion resistance of high-carbon ferrochrome FeCrV15 clad coatings for agricultural and mining applications. Laser cladding techniques were employed to deposit coatings on steel substrates, and the samples were subjected to comprehensive material characterization, including microhardness testing, wear studies, and electrochemical polarization. Results reveal that TiB₂ addition led to visible reactions during deposition, resulting in decreased hardness compared to pure FeCrV15 coatings. Moreover, TiB₂ incorporation adversely affected the anti-corrosion properties of the coatings, although FeCrV15 coatings exhibited superior corrosion resistance compared to FeCrV15 + TiB₂ coatings. Tribological evaluations showed that all coatings exhibited better anti-wear capabilities compared to the steel substrate, with varying degrees of improvement influenced by TiB2 concentration and laser beam power. Overall, FeCrV15 deposits demonstrated superior anti-wear and anti-corrosion properties compared to FeCrV15 + TiB₂ coatings and attributed to increased convergence of carbide particles and higher grain-boundary density. This research contributes to understanding the intricate interplay between carbide reinforcement and matrix structure in Fe-based hard facings, providing insights for optimizing coating performance in demanding industrial applications.

Large temperature gradient will produce high residual stress during laser powder bed fusion (LPBF). In metal matrix composites (MMCs), the thermal-induced stress distributes complexly. It is indispensable to study the interfacial stress of MMCs during LPBF process. In this study, a multi-phase finite element model was established to reveal the temperature and stress distributions of TiB₂/Al-Si composites fabricated by LPBF. Influences of particulate geometries on the residual stress were also analyzed in the model. The numerical results indicate that the residual stress in the composites was induced by high temperature gradient and coefficient of thermal expansion mismatch simultaneously. TiB₂ reinforcing particles suffer large compressive stress perpendicular to the interface. In the matrix, the stress component at the interface is negative and increases rapidly with distance from the particle increases. The interfacial compressive stress lessens the mean tension stress in the nearby regions of the matrix. Maximum von Mises stress is generated at the interface in the matrix, which may cause defects and cracks. High interfacial stress was generated in the vicinity of the vertex of cubic particles and the internal stress large in ellipsoidal particles, indicating that particles with fewer edges and smaller slenderness ratio possess greater thermal shock resistance.

Cold spray additively manufactured (CSAM) aluminum 6061 components are characterized by heterogeneous compressive residual stresses induced during manufacturing. This heterogeneity is further compounded by spatial variations in microstructures and mechanical properties, leading to poor inter-particle (intersplat) bonding and significant marring of overall component performance. Thermal post-processing is a keenly researched method for recovering mechanical toughness by enhancing intersplat bonding and altering highly concentrated residual stress distributions. The current work incorporates a modified microscale–mesoscale material model into a viscoplastic self-consistent simulation framework to capture material response in the as-sprayed and post-processed states. The updated model incorporates physically informed parameters emphasizing residual stresses measured experimentally through X-ray diffraction. The model calibrated using experimental tests and published literature was able to predict the stress–strain response of CSAM parts at post-heat-treated conditions. Results of the parametric study showed the significance of intersplat boundary effects on the overall yield and strain hardening of the CSAM parts. Without any information on the processing conditions of CSAM parts, the modified plasticity model predicted the deformation response using information gathered from microstructure characterization.

Residual stress is responsible for various engineering failures in cases where the magnitude of residual stress exceeds the ultimate strength. With the aim of minimizing the residual stress induced in the machining of AISI 1045 steel, different machining parameters (speed, feed, depth of cut) and the output variables were experimentally investigated in this research. Series of specimens were produced using different machining parameters, and the residual stress in each was measured. When a material is subjected to external forces or thermal treatments, residual stresses can be introduced due to changes in the lattice spacing of the material. These changes in lattice spacing are detected using a non-destructive method based on the x-ray diffraction (XRD) technique. The equipment used is iXRD with MGR40P- Stress measurement system, PROTO CANADA make. The PROTO XRDWIN 2.0 software was an integral part of the XRD machine, which records all the necessary data, calculations and provides the user with surface residual stresses values. Data analysis and the process parameters were optimized using Taguchi L9 orthogonal design of experiments. To determine the effects of the machining parameters on residual stress, Analysis of Variance (ANOVA) was used. The results indicate that the feed rate is only statistically significant parameter on the residual stress with the largest main effect. The optimal setup of machining parameters that cause the lowest residual stress of − 145.4 MPa was identified, with a speed of 710 m/min, a feed of 80 mm/min, and a DOC of 0.2 mm.

The machined surface residual stress plays a critical role in stress corrosion cracking resistance and fatigue performance of austenitic stainless steels. Controlling the residual stress by changing machining parameters is an effective way to improve the service performance of components. This paper explores the effects of processing parameters and tool geometric parameters on residual stress by establishing an analytical model for residual stress evaluation on machined surface. Considering the thermo-mechanical coupling effects of machining, a multi-physics framework of orthogonal cutting process is built up. From the coupling mechanical and thermal loads, the variations of stress, strain and temperature are modelled by an elastoplastic procedure. Based on the mechanism of residual stress and the loading-unloading model, the prediction of residual stress is achieved. Experimental tests are conducted for model validation. By simulating the cutting processes under different conditions and analyzing the main factors that affecting the stress/strain and temperature fields, the effects of cutting parameters and tool geometric parameters on residual stress are revealed.

Microwave sintering (MS) technology is used to fabricate UNS R56320 (Ti-3Al-2.5V)-xWC composite at 1200 °C. In the matrix, tungsten carbide (WC) is reinforced with various weight percentages of 0.5, 1.0, 1.5, and 2.0. A field emission scanning electron microscope is used to characterize the composites (FE-SEM). X-ray diffraction was used to analyze the composites’ phase analysis (XRD). Microstructure, wear at high temperatures, and corrosion behavior are evaluated. For the composites at different temperatures of 30 °C, 50 °C, 100 °C, 150 °C, and 200 °C, the high-temperature wear is examined. The outcomes show improvements in the behaviors of corrosion and wear at high temperatures. TAFEL polarization is used to evaluate the corrosion behavior of the composites in a neutral chloride solution (3.5% NaCl). The composite material UNS R56320-2WC has a maximum wear rate of 0.49 × 10⁻³ mm³/m and a coefficient of friction of 0.50. A higher level of corrosion resistance than other composites is also possessed by UNS R56320-2WC composite.

The properties and microstructure of Type 304L stainless steel produced by two additive manufacturing (AM) methods—directed energy deposition (DED) and powder bed fusion (PBF)—are evaluated and compared. Localized heating and steep temperature gradients of AM processes lead to significant residual stress and distinctive microstructures, which may be process-specific and influence mechanical behavior. Test data show that materials produced by DED and PDF have small differences in tensile strengths but clear differences in residual stress and microstructural features. Measured fatigue crack growth rates (FCGRs) for cracks propagating parallel to and perpendicular to the build directions differ between the two AM materials. To separate the influences of residual stress and microstructure, K-control test procedures with decreasing and constant stress intensity factor ranges are used to measure FCGRs in the near-threshold regime (crack growth rates ≤ 1 × 10⁻⁸ m/cycle). Residual stress is quantified by the residual stress intensity factor, K_res, measured by the online crack compliance method. Correcting the FCGR data for differences in K_res brings results for specimens of the two AM materials into agreement with each other and with results for wrought specimens, when the latter are corrected for crack closure. Differences in microstructure and tensile strength have an insignificant influence on FCGRs in these tests.

In the paper industry, machine circular knives are used in the cutting process to provide industrial quality cuts on a variety of products. In the production of paper rolls, they cut the long-rolled paper products into commercial sizes. For this application, the high-alloyed ledeburitic cold work tool steel, DIN EN 1.2379 (X153CrMoV12; AISI D2), in the secondary hardened heat-treated condition has become the widely used industry solution. However, its heat treatment is a very energy-intensive production process. It consists of a quenching from an austenitizing temperature above 1050 °C, followed by three high-temperature tempering steps of more than 500 °C. In the study, the heat treatment process was optimized for energy efficiency, resulting in superior material properties with lower energy consumption. The most promising low energy heat treatment developed in the laboratory was reproduced in the industrial scale, and the required energy consumption was quantified. Subsequently, the resulting properties of the tools such as hardness, wear resistance and fracture toughness were determined. The energy production costs and mechanical properties of the tool steel were evaluated in comparison to conventional production methods. The newly applied heat treatment condition showed very promising and positive results in all analyzed parameters.

Present study discusses about a technique for producing high-purity Cr₂AlC MAX phase materials and gaining insight into their thermal behavior for high-temperature applications. The research conducted involved synthesizing a pure layered ternary carbide Cr₂AlC MAX phase material by mixing powders of Chromium, Aluminum, and Carbon and then subjecting them to two-step pressureless sintering process in argon atmosphere. First step involves the annealing of ball-milled mixture at 750 °C for 2 h followed by the second step in which the annealed mixture is subjected to heat-treatment at 1350 °C for 2 h. Analysis using XRD and Raman techniques revealed that the synthesized product consists of Cr₂AlC phase, without any impurities. SEM studies confirmed that the Cr₂AlC had a layered topography, while EPMA analysis indicated that the atomic percentage of Cr, Al, and C was consistent with the XRD phase analysis. XPS investigations confirmed the presence of Cr-C bonds representing M_n+1X_n of the MAX phase material. TG-DSC results showed an approximately 2% increase in weight. The Cr₂AlC phase exhibited an endothermic pattern below 725 °C, an exothermic pattern above it, and did not decompose up to 1400 °C in vacuum environment. High-temperature XRD analysis at various temperatures also confirmed no formation of Al₂O₃ or CrO impurity compounds.

The plasma electrolytic oxidation (PEO) technology was used to prepare ceramic coating on the surface of titanium alloy to prevent the galvanic corrosion of AH36/TC4(PEO). The results showed that after PEO treatment, ceramic coating with micropores was formed on the substrate surface. When the voltage was low, the pore size was small. With the increase of voltage, the thickness and the pore sizes of the coating increased. After PEO process, the average galvanic corrosion rate was reduced by 60%, and the number of pitting pits on the AH36 surface in the galvanic pair was reduced. The tensile strength and elongation of AH36 coupled with TC4(PEO) decreased by 4.0% and 11.9%, respectively. The contents of the corrosion products Fe₂O₃·H₂O and FeO(OH) decreased, and the corrosion area of the tensile specimen was evidently reduced. Therefore, the PEO process can effectively reduce the galvanic corrosion susceptibility of AH36/TC4(PEO), alleviate the reduction degree of ductility and toughness of anode AH36, and enhance the corrosion resistance performance.