Microstructure Properties Research Articles

Effect of microalloying and isothermal transformation on the microstructure and mechanical properties of SWRH82B steel

Effect of microalloying and isothermal transformation on the microstructure and mechanical properties of SWRH82B steel

Investigation on the microstructure-mechanical property correlation in dissimilar steel welding between HARDOX and YS700 steel

ABSTRACT Weld structure evaluation is an important method for automotive engineers to avoid fracture at the joints between two similar or dissimilar metals. The enhanced strength of weld structures is always advantageous of automotive structure to withstand continuous and high loading operations. The conventional vehicles use mild steel (YS700) with the yield strength up to 500 MPa for its load body applications. However, these joints are prone to failure at higher loading conditions. Hence, we have implemented dissimilar welding between HARDOX steel and YS700 steel to investigate the microstructure and mechanical properties correlation. In this process MIG welding is employed for the fusion of these dissimilar metals, with a subsequent analysis focused on correlating their properties. Tensile test results show the dissimilar welded structure (HARDOX-YS700 steel) exhibits yield strength of 601 MPa, which is higher than the similar joining HARDOX–HARDOX welded structure. These results indicate enhanced mechanical strength of dissimilar welding joints. Further, microstructure is analysed through SEM and it shows brittle fracture in the case of base metal HARDOX–HARDOX weld joints. Whereas, dissimilar weld microstructure indicates the quasi-cleavage fracture. This study paves foundation for dissimilar welding for the high strength weld joints which can withstand high load condition.

Microstructural and mechanical properties of boron carbide and graphite particles based AA6063 hybrid composite

The present research work focuses on the production of AA6063 hybrid (graphite (Gr) and boron carbide (B4C)) matrix composites to improve the mechanical characteristics of the AA6063 matrix. The AA6063 hybrid composites were developed with 4% weight percentage (wt%) of Gr and varying wt% (3, 6, 9 and 12%) of B4C microparticles using the stir casting method. The microstructural and mechanical properties, including microhardness, % elongation, and ultimate tensile strength (UTS), of the developed AA6063 hybrid composite were evaluated. The microstructural evolution was performed using optical microscopy and scanning electron microscopy to reveal the grain structure and the dispersion pattern of Gr and B4C particles, respectively. The findings obtained from AA6063 hybrid composites revealed that the microhardness and UTS were enhanced at the expense of a decrease in % elongation with the addition of Gr and B4C particles. The highest UTS of 152.3 MPa was found in the AA6063 hybrid composite with 4 wt% of Gr and 9 wt% of B4C. Whereas a maximum hardness of 79.2 HV was found in the AA6063 hybrid composite with 4 wt% of Gr and 12 wt% of B4C.

Multifunctional Polymeric Bioactive Coatings on Ti Implants through the Drug Delivery Approach: In Vitro Corrosion Resistance, Biocompatibility, and Antibacterial Characteristics.

In the current study, we developed a controlled drug delivery system using a polymeric matrix composed of biopolymer poly(vinylidene fluoride) (PVDF) and ciprofloxacin (CPF)-loaded titanium (Ti) nanotubes (TNTs) on Ti substrates for biomedical applications. The TNT arrays over the Ti surface were obtained through an anodization route. The PVDF coatings were dip-coated on TNT-Ti loaded with CPF. The chemical, microstructure, and surface properties of the TNTs and coated surfaces were characterized using FTIR, XRD, transmission electron microscopy (TEM), scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS), and surface hydrophilicity analyses. The performance of the implant surfaces was evaluated through in vitro corrosion studies in simulated body fluid (SBF), biocompatibility with MG63 cells, and antibacterial properties. The results revealed that the PVDF/0.1CPF coatings exhibited sustained release of CPF from the polymer matrix at a linear rate and releasing profile for 168 h. PVDF/0.1CPF coating showed decreased corrosion current density (4.457 × 10-9 A/cm2) by 2 orders of magnitude than that of the Ti substrate, indicating enhanced corrosion protection in the SBF. PVDF/0.1CPF coating showed an antibacterial efficacy of 84.44% against Escherichia coli and 88.33% against Bacillus licheniformis after 24 h. The biocompatibility result showed that after 5 days of culturing, the PVDF/0.1CPF was pointedly higher than that of the pure PVDF and uncoated specimens. Additionally, after 7 days of culture, the quantity of cells on the PVDF/0.1CPF coating continued to increase significantly, whereas the bare specimens and pristine PVDF showed a lower rate of proliferation. The proposed biocompatible polymeric coatings hold synergic antibacterial and corrosion-resistant potential for biomedical applications.

Microstructure and Optical Properties of Y1.8La0.2O3 Transparent Ceramics Prepared by Spark Plasma Sintering

Microstructure and Optical Properties of Y1.8La0.2O3 Transparent Ceramics Prepared by Spark Plasma Sintering

Tracing the Origins: Byzantine Lime Mortars from Anaia and St. Jean Churches (Western Türkiye) and Provenances of Natural Stone Aggregates

The aim of this study is to determine the provenances of natural stone aggregates of the lime mortars from the St. Jean and Anaia Churches, which represent two of the most significant Byzantine buildings in Western Türkiye. With this aim, the characterization study was conducted to define the physical properties and raw material compositions of lime mortars; hydraulic properties of the binders; mineralogical and chemical compositions, microstructural properties of lime, binders and aggregates; geochemical characteristics and pozzolanic activities of aggregates. The analyses were determined using X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and thermogravimetric analysis (TGA). Furthermore, field observations and analytical studies were paired with the characterization results to determine the possible provenances. Analytical studies demonstrated that natural stone aggregates exhibited highly pozzolanic properties, which imparted hydraulicity to lime mortars. The macrostructure of the natural stone aggregates exhibited angular characteristics and a diverse lithological composition derived from the older brecciated clastics of the Menderes Massif. The fine-grained volcanic matrix of the aggregates was predominantly dacitic or rhyolitic in character, possibly derived from a breccia matrix composed of volcaniclastic materials. The findings suggested that the provenance of the natural stone aggregates were the breccia accumulation regions around Ayasuluk (Selçuk) for the St. Jean Church and Söke-Germencik for the Anaia Church. The deliberate selection of natural stone sources to produce hydraulic lime mortars shows a conscious relationship with the surrounding geology during the Byzantine period.

Sustainable fly ash‐based geopolymer composites: The influence of RAP aggregates and silica fume on strength, durability, and microstructural properties

Sustainable fly ash‐based geopolymer composites: The influence of <scp>RAP</scp> aggregates and silica fume on strength, durability, and microstructural properties

Effects of Bi2O3 as sintering aid on the microstructure and electrical properties of La2Ti2O7 ceramics

Effects of Bi2O3 as sintering aid on the microstructure and electrical properties of La2Ti2O7 ceramics

The Influence of Ti and Al on the Evolution of Microstructure and Mechanical Properties in Medium-Entropy and High-Entropy Alloys Based on AlxTixCrFe2Ni2

The Influence of Ti and Al on the Evolution of Microstructure and Mechanical Properties in Medium-Entropy and High-Entropy Alloys Based on AlxTixCrFe2Ni2

Effect of Friction Stir Processing on the Microstructure, Mechanical and Tribological Properties of Silicon Nitride Reinforced ZE43 Magnesium Composite

Effect of Friction Stir Processing on the Microstructure, Mechanical and Tribological Properties of Silicon Nitride Reinforced ZE43 Magnesium Composite

Connectivity related to major brain functions in Alzheimer disease progression: microstructural properties of the cingulum bundle and its subdivision using diffusion-weighted MRI

BackgroundThe cingulum bundle is a brain white matter fasciculus associated with the cingulate gyrus. It connects areas from the temporal to the frontal lobe. It is composed of fibers with different terminations, lengths, and structural properties, related to specific brain functions. We aimed to automatically reconstruct this fasciculus in patients with Alzheimer disease (AD) and mild cognitive impairment (MCI) and to assess whether trajectories have different microstructural properties in relation to dementia progression.MethodsMulti-shell high angular resolution diffusion imaging−HARDI image datasets from the "Alzheimer's Disease Neuroimaging Initiative"−ADNI repository of 10 AD, 18 MCI, and 21 cognitive normal (CN) subjects were used to reconstruct three subdivisions of the cingulum bundle, using a probabilistic approach, combined with measurements of diffusion tensor and neurite orientation dispersion and density imaging metrics in each subdivision.ResultsThe subdivisions exhibit different pathways, terminations, and structural characteristics. We found differences in almost all the diffusivity metrics among the subdivisions (p < 0.001 for all the metrics) and between AD versus CN and MCI versus CN subjects for mean diffusivity (p = 0.007–0.038), radial diffusivity (p = 0.008–0.049) and neurite dispersion index (p = 0.005–0.049).ConclusionResults from tractography analysis of the subdivisions of the cingulum bundle showed an association in the role of groups of fibers with their functions and the variance of their properties in relation to dementia progression.Relevance statementThe cingulum bundle is a complex tract with several pathways and terminations related to many cognitive functions. A probabilistic automatic approach is proposed to reconstruct its subdivisions, showing different microstructural properties and variations. A larger sample of patients is needed to confirm results and elucidate the role of diffusion parameters in characterizing alterations in brain function and progression to dementia.Key PointsThe microstructure of the cingulum bundle is related to brain cognitive functions.A probabilistic automatic approach is proposed to reconstruct the subdivisions of the cingulum bundle by diffusion-weighted images.The subdivisions showed different microstructural properties and variations in relation to the progression of dementia.Graphical

Effects of different heat treatment methods on the mechanical properties and structures of Al-6061

ABSTRACT The Al 6061 alloy is mainly hardened by the precipitation of the secondary Mg2Si and ternary (Al-Mg-Si) eutectic. In this work, the Al 6061 plates have been heat-treated by four different methods and thereafter the tensile strength, hardness and microstructural attributes have been compared. The first plate was kept untreated or in ‘as received’ condition. The remaining four samples were solution annealed (SA) at 350°C for 1.5 h of soaking time. The SA was followed by (1) only water quenching (WQ) in the 2nd sample; (2) water quenching + ageing (WQ + Ag) in the 3rd sample; (3) only furnace cooling (FC) in the 4th sample, and (4) furnace cooling + ageing (FC + Ag) in the 5th sample. The ageing was performed at 150°C for 4 h of holding period. The study revealed that WQ increases the ductile behaviour of the Al 6061 alloy but with a loss of ultimate tensile strength (UTS) and yield strength (YS). The WQ + Ag sample showed an improvement of 23% in elongation, while the FC sample had the lowest UTS and YS. The WQ + Ag sample showed a slight improvement in UTS and YS, while the FC + Ag sample recovered UTS, YS, and hardness, which were dropped during plain FC.

Effect of Preheating on Microstructure and Mechanical Properties in Mild Steel Arc Weld Joints

Effect of Preheating on Microstructure and Mechanical Properties in Mild Steel Arc Weld Joints

Multiscale finite element modeling to achieve the mechanical properties of FSPed and SiC-reinforced austenitic 316L stainless steel produced by selective laser melting

In this study, austenitic 316L stainless steel produced by Selective Laser Melting (SLM) was reinforced with SiC nanoparticles using Friction Stir Processing (FSP). The microstructure and mechanical properties of the resulting nanocomposite were experimentally investigated, and multiscale finite element modeling was performed using the Mori-Tanaka homogenization method to predict its macroscopic mechanical properties based on microstructural interactions. SLM-fabricated samples were reinforced via FSP with 10 vol% SiC and subjected to tensile tests. Results showed a 17% increase in tensile strength for the solely FSP-processed sample compared to the as-built SLM sample (from 570 MPa to 670 MPa), with a slight improvement in ductility (from 27% to 29%). The addition of SiC nanoparticles further increased tensile strength to 743 MPa, while ductility decreased to 23%. This represented a 30% and 11% strength increase compared to the as-built SLM sample and the solely FSP-processed sample, respectively. The strength improvement was attributed to the dispersion of particles along grain boundaries and within grains, as well as to recrystallization and grain refinement induced by FSP. The stress-strain curves from finite element modeling aligned closely with experimental results. Predicted tensile strength and ductility were 668 MPa and 30% for the solely FSP-processed sample, and 740 MPa and 25% for the nanocomposite.

Enhanced Thermoelectric Properties of AgSb1-xPbxBiySe2 Achieved via Microwave Smelting Combined with Spark Plasma Sintering.

In this study, two series of thermoelectric (TE) materials, AgSb1-xPbxSe2 (x = 0.00, 0.035, 0.04, 0.045, and 0.05) and AgSb0.955Pb0.045BiySe2 (y = 0.01, 0.015, 0.02, and 0.025), were fabricated that are achieved via microwave smelting (MS) combined with spark plasma sintering (SPS). Although Pb doping effectively increased the carrier concentration (n) of the AgSb1-xPbxSe2 materials, it substantially restricted the improvement in carrier mobility (μH), leading to a nonsignificant enhancement in the dimensionless figure of merit (ZT). To address this issue, AgSb1-xPbxSe2 was doped with Bi to optimize n and μH. The phase composition, microstructure, and electrical and thermal transport properties of the materials were characterized in the temperature range of 300-723 K. The AgSb0.955Pb0.045Bi0.025Se2 material exhibited a maximum power factor of 720 μWK-2 m-1 at 723 K and a reduced lattice thermal conductivity of 0.36 Wm1- K-1. Consequently, a ZT value as high as 1.23 was obtained at 723 K. This study demonstrates that microwave smelting - SPS is an efficient and environmentally friendly method for the synthesis of Pb- and Bi-doped AgSbSe2 materials with excellent TE transport properties.

Effect of holding time and AgCuTi composite filler on microstructure and mechanical properties of GH4169/ SiC vacuum brazed joints

Effect of holding time and AgCuTi composite filler on microstructure and mechanical properties of GH4169/ SiC vacuum brazed joints

Effect of temperature and deposition power on microstructure and properties of magnetron sputtered thin AlN coatings

This paper demonstrates the influence of deposition parameters (temperature, power and time) and stoichiometric composition of thin aluminum nitride (AlN) coatings, the thickness of which varied from 320 to 1100[Formula: see text]nm deposited by DC reactive magnetron sputtering on their microstructure, mechanical and microtribological properties. The investigation revealed that high-deposition power (150[Formula: see text]W) and temperature ([Formula: see text]C) lead to sputtering of coatings with high roughness, low mechanical and high microtribological properties. Such a phenomenon occurred due to the formation of a coarse-grained structure, high porosity and dendritic growth of the coating, which was observed on their cross-sections. Reducing the deposition temperature to [Formula: see text]C and power to 80–100[Formula: see text]W allowed to obtain a fine-crystalline structure demonstrating low-roughness values with crystallites evenly and compactly distributed over the surface. Such coatings showed higher mechanical and low microtribological properties. Surface resistivity was lower on coatings with a fine crystalline structure and correlated with the nitrogen content of the coating. In the course of the research, it was demonstrated that the optimal combination of microstructure, mechanical, microtribological properties and electrical resistivity for practical use in micro- and nanosensory applications may be achieved for the AlN coating with the thickness of 320[Formula: see text]nm and 29.71[Formula: see text]at.% N, deposited at [Formula: see text]C, 100[Formula: see text]W and 20[Formula: see text]min. Such a coating possesses the highest values of mechanical properties, low roughness and specific surface resistance, as well as low coefficient of friction and specific volumetric wear compared to all coatings under study.

Additive Manufacturing of TiBw-Reinforced Titanium Matrix Composites Fabricated by Electron Beam Melting: Microstructure and Mechanical Properties

TiBw reinforced titanium matrix composites (TMCs) are the most promising engineering materials in aerospace and transportation owing to their excellent properties such as lightweight, high strength, wear resistance. The electron beam powder bed fusion (EB-PBF) characterized by its rapid solidification process during the manufacturing, which can effectively controlling the microstructure and mechanical properties of DRTMCs. The state of feedstock used in EB-PBF has a significant influence on the microstructure and mechanical properties of DRTMCs prepared by EB-PBF. However, there is no commercial feedstock available for EB-PBF fabricating DRTMCs. The disadvantages of premixed ball-milled powder are degraded flowability or incomplete reaction and agglomeration of reinforcements, which causes metallurgical defects in the as-fabricated composites. These issues severely affect the stability of mechanical properties of DRTMCs prepared by EB-PBF. The introduction of TiBw led to the formation of melt pool structure. At the boundary of the melt pool, TiBw exhibits an equiaxed continuous network distribution, while at the center of the melt pool, TiBw exhibits a columnar continuous network distribution; Moreover, the introduction of TiBw resulted in a 75% grain refinement, a 40% increase in yield strength, a 54% increase in tensile strength, and a decrease in elongation (13.2%) in the composite material. The improvement in strength of Ti-TiBw composite material prepared by EBM is due to grain refinement and the good load transfer effect generated by high aspect ratio TiBw, while the decrease in plasticity of the composite material is due to the connectivity failure of TiBw on the matrix. Based on the current research of DRTMCs prepared by EB-PBF, the future research trend focus on TiBw reinforced DRTMCs prepared by EB-PBF is discussed.

POST-HEAT TREATMENT IN METAL ADDITIVE MANUFACTURING: A COMPREHENSIVE REVIEW OF PROCESSES, MICROSTRUCTURE EVOLUTION, AND MECHANICAL PROPERTIES

Metal Additive Manufacturing (MAM) has revolutionized the manufacturing of intricate three-dimensional structures. Sometimes, the material properties and microstructures of metals produced by additive manufacturing (AM) are often worse than those created using traditional manufacturing methods. Mechanical characteristics and microstructure of AM-made metals can be enhanced with post-heat treatment (PHT). This paper reviews and discusses the various types of PHT techniques, including solution treatment (ST), aging, Isostatic Hot Pressing, and precipitation hardening. In this study, several characterization methods, such as mechanical testing, hardness testing, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM), are utilized to investigate how the microstructure and mechanical properties of the printed components change after being subjected to PHT. The study results give important information about each selected metal’s most effective heat treatment conditions. This lets the microstructure and mechanical properties of the printed parts be tuned effectively. The paper has reviewed the various PHT effects in MAM on various metallic materials such as Stainless Steel, Maraging steel, Aluminum, and Titanium alloys.

On the role of rotational speed in P-FSSW dissimilar aluminum alloys lap weld

Abstract One of the most promising solid-state methods for joining high-strength aluminum alloys, friction stir spot welding (FSSW), remains hindering due to formation of the keyhole defect. This paper presents its promising variation as a probeless-friction stir spot welding (P-FSSW) assisted by flat featureless shoulder. Based on the prior arguments on the feasibility of this method in joining aluminum alloys, present work provides in-depth study on the effect of rotational speed on microstructure, phase transformations, and final properties of dissimilar aluminum plates, studies using scanning electron microscopy (SEM), occupied by electron backscattered diffraction (EBSD) method and energy-dispersive X-ray spectroscopy (EDS) analysis. The resulting properties was examined through microhardness measurements and tensile-shear testing. Results showed that rotational speed plays a crucial role in determining the intensity of material softening, its flow, and mechanical properties. Uniform heating and circumferential material flow helped eliminate edge hook defects using a featureless tool during P-FSSW. The microstructure development followed progressive plastic deformation was accompanied by a gradual transition between continuous dynamic recrystallization (CDRX) and dynamic recovery (DRV) process. The re-precipitation of the Al2CuMg phase restricted grain growth by pinning recrystallized grains within the stir zone (SZ). Mechanical tests indicated improved joint strength, suggesting that P-FSSW could produce high-quality, lightweight joints suitable for automotive and aerospace applications.