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The ultimate tensile strength (UTS) of gray cast iron (GCI) can be affected by numerous parameters due to its complex microstructures. To further understand the UTS of GCI, it is necessary to evaluate the impact of various parameters. Herein, a UTS prediction method based on microstructure features and machine learning (ML) algorithms is proposed. The six regression algorithms, namely, Bayesian Ridge, Linear Regression, Elastic Net Regression, Support Vector Regression, Gradient Boosting Regressor (GBR), and Random Forest Regressor are used to develop the prediction models. The predicted results show that the GBR has the best prediction performance for the predicted UTS and the error bands within 5%. The feature importance indicates that matrix hardness has the greatest effect on the UTS in the ML models. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are widely used as implant biomaterials due to their well mechanical properties and biological compatibilities. Nb and Mn are well‐known alloying elements with biological potential. Herein, the Ti–Mn–Nb phase equilibria at 900 °C (Ti‐rich region) is determined and published. According to the β single‐phase field in this phase diagram (at 900 °C), Ti–xMn–yNb (x = 4, 10, 16; y = 2, 8, 14, at%) alloys are selected and fabricated which are suited for solution heat treatment. The Ti–Mn–Nb alloys are investigated by optical microscopy (OM), X‐ray diffraction (XRD), and mechanical testing. A unique diffraction pattern (interpreted as occurrence of a transition phase) is observed by transmission electron microscopy (TEM) in Ti–10Mn–2Nb. In the in vitro evaluation, the human osteoblasts (MG63) adhere well and proliferate on the surface of Ti–xMn–yNb (x = 4, 10; y = 2, 8, 14, at%). According to cell culture experiments, the alloys are nontoxic to human osteosarcoma cells in comparison with pure titanium. Based on a performed screening study, different titanium alloys Ti–4Mn–yNb (y = 2, 8, 14) appear as the biomaterial with the highest potential around 700 MPa ultimate tensile strength and 9–10% elongation. [ABSTRACT FROM AUTHOR]

The goal of present research is to investigate the effect of thickness of aluminum, stainless steel and driver sheets on the ultimate tensile strength, weld width and hardness of aluminum‐stainless steel joint in the electromagnetic welding. First, the finite element analysis was applied to predict the joint formation between aluminum and stainless steel sheets by using the weldability window. Then, the experiments were conducted using the response surface methodology and desirability function to attain the desirable values of sheet thickness. Eventually, the microstructure of weld interface was observed by optical and scanning electron microscopy to evaluate the quality of welds. It was observed that the values of ultimate tensile strength, weld width and hardness can be simultaneously improved by selecting the thickness of aluminum, stainless steel and driver at 0.78 mm, 0.37 mm and 0.96 mm respectively. The microstructure analysis exhibited that the detrimental effects of intermetallic layers on the weld strength can be limited by reducing the thickness of intermetallic to 4 μm. [ABSTRACT FROM AUTHOR]

Understanding biomass interaction is critical for bottom‐up design of novel biocomposites and existing manufacturing processes. In this study, interactions between bioadhesives (lignin, carbohydrates, or proteins) and fibers (cellulosic fiber or wood fiber) are elucidated via experimental bonding strength tests and molecular dynamics (MD) simulations. Experimental results reveal a good, nearly linear correlation between the composite's density and tensile strength, a finding which has rarely been reported previously. Adhesives are compared to one another: soy protein isolate is found to be the best for pinewood fiber, while apple pectin and soy protein isolate are the best for α‐cellulose fiber. It is further shown that the fiber type plays an important role in defining the composite strength. In agreement with experiments, the MD simulations at nanoscale predict a linear strength to density correlation; this is driven by the hydrogen bond (H‐bond) content in the composite. The H‐bond content is also found to determine the varied performances of different adhesives. [ABSTRACT FROM AUTHOR]

Strength and hardness of metallic materials are reported to correlate in a specified form. Among various equations, yield strength is generally converted from Vickers hardness (HV) via a three‐time relation due to the simple and nondestructive nature of hardness testing. Herein, a through literature review is made and data of strength and HV for face‐centered cubic (FCC) and body‐centered cubic (BCC) high‐entropy alloys (HEA) are collected. The yield strength and HV visibly deviate from the three‐time relation, but the ultimate tensile strength and HV roughly follow the three‐time relation. New linear relationships, which are universally applied to convert HV to yield strength and ultimate tensile strength, are proposed. [ABSTRACT FROM AUTHOR]

Currently, the growth of material data from experiments and simulations is expanding beyond processable amounts. This makes the development of new data‐driven methods for the discovery of patterns among multiple lengthscales and time‐scales and structure‐property relationships essential. These data‐driven approaches show enormous promise within materials science. The following review covers machine learning (ML) applications for metallic material characterization. Many parameters associated with the processing and the structure of materials affect the properties and the performance of manufactured components. Thus, this study is an attempt to investigate the usefulness of ML methods for material property prediction. Material characteristics such as strength, toughness, hardness, brittleness, or ductility are relevant to categorize a material or component according to their quality. In industry, material tests like tensile tests, compression tests, or creep tests are often time consuming and expensive to perform. Therefore, the application of ML approaches is considered helpful for an easier generation of material property information. This study also gives an application of ML methods on small punch test (SPT) data for the determination of the property ultimate tensile strength for various materials. A strong correlation between SPT data and tensile test data was found which ultimately allows to replace more costly tests by simple and fast tests in combination with ML. [ABSTRACT FROM AUTHOR]

The average strain energy density (ASED) criterion applied to design of notched mechanical components has been achieved a considerable success over the years thanks to its numerous advantages including the need for a relatively coarse mesh, the use of a scalar rather than vector quantity and the ability to compare the strength of parts with different notch angles. It is known that adhesively bonded joints mechanical strength is governed by the stress singularity arising near the intersection between the adhesive‐substrate interface and the free surface of the bonded joint, even without notches. This is due to the different elastic material properties of the adhesive compared to those of the substrate that induces a constitutive stress singularity. This phenomenon makes the strain energy density criterion particularly suitable for the design of bonded joints, as well. This contribution is aimed at applying the ASED criterion to the static strength assessment of bonded joints. Experimental results taken from literature were found in good agreement with those predicted by the ASED approach. [ABSTRACT FROM AUTHOR]

Investigation of mechanical and vibrational properties of nano‐structures using the analytical methods would be time‐consuming. Therefore, using a semi‐empirical method would reduce the time needed to investigate materials characterisation. One of the semi‐empirical approaches is molecular dynamics. In this Letter, the large‐scale atomic/molecular massively parallel simulator software is used to simulate the mechanical and vibrational behaviour of a nitrogen‐ and boron‐doped 24.04 × 51.13 Å graphene nano‐sheet. The natural frequencies, Young's modulus, and ultimate tensile strength (UTS) are studied. By adding impurity to the nanosheet and increasing its density, Young's modulus, UTS, and natural frequencies were decreased. The decrease in tensile properties was more significant in the case of boron impurity. When the boron (nitrogen) impurity increased to about 20%, Young's modulus and the first natural frequency were decreased 7.1% (9%) and 16.8% (73%), respectively. This illustrates that Young's modulus and natural frequencies are directly related. Therefore, for the same dimensions and boundary conditions, it is obvious that the increase in impurity content has reduced the natural frequencies of the nanostructure. [ABSTRACT FROM AUTHOR]

Adaptive properties and complex shapes of modern day soft matter components create a challenge for materials applications where mechanical properties of intricate fabricated components cannot be determined from conventional invasive and destructive mechanical tests. In particular, challenges arising from variable mechanical properties of polydimethylsiloxanes (PDMSs) constantly attract wide‐scale attention in the fields of material sciences, biological systems, and microfluidics. Herein, a noninvasive and nondestructive strain‐induced infrared spectroscopic method (S‐FTIR) is developed. S‐FTIR is a method that maps thermo‐mechanical response of PDMS to its strain‐induced spectral fingerprint. From the results of this study, strong correlations of up to 95% between spectral fingerprint of PDMS and its corresponding nonlinear thermo‐mechanical response is seen. Given the nature of these results, it is expected that S‐FTIR will provide an interesting new analytical approach to understand soft materials and allow for the characterization of micro and nanoscale devices composed of these polymeric materials as well. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 359–367 Strain‐induced infrared spectroscopic method (S‐FTIR), a scale independent nondestructive and noninvasive experimental characterization tool, is developed for determining thermo‐mechanical properties of polydimethylsiloxanes (PDMS). S‐FTIR maps strain‐induced spectral fingerprints of PDMS to its thermo‐mechanical response. From the results, it is seen that S‐FTIR is capable of predicting the thermo‐mechanical response of PDMS with an accuracy of up to 95%. Hence, S‐FTIR is a reliable tool for characterizing components made of PDMS. [ABSTRACT FROM AUTHOR]

The atmospheric corrosion behavior of 6061 aluminum alloy exposed in industrial and marine atmosphere environments for 36 months has been investigated by weight loss test, tensile strength test, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and optical microscope. The results of weight loss and tensile strength showed that, compared with industrial atmosphere environment, 6061 presented higher corrosion susceptibility in marine atmosphere environment. XPS analysis indicated that the major constituents of corrosion products formed in industrial atmosphere environment were aluminum hydroxide, aluminum oxide, and aluminum sulfate. In marine atmosphere environment, corrosion products mainly contained aluminum chloride, aluminum hydroxide, and aluminum oxide. Surface morphologies analysis revealed that the corrosion products formed in industrial atmosphere environment were agglomerated and uneven. The corrosion products formed in marine atmosphere environment presented polygon shape, and revealed some broad cracks. Cross-section morphologies analysis manifested that 6061 suffered pitting attack in both types of atmosphere environments, and the intensity of pitting attack in marine atmosphere environment was much more serious than that in industrial atmosphere environment. [ABSTRACT FROM AUTHOR]

Microstructural evolution and mechanical properties of friction stir welded AA7075-T6 aluminum alloy were examined. Grain structure and precipitate evolution in the stir zone and heat-affected zone were evaluated using optical microscope and differential scanning calorimetry. A significant grain refinement and dissolution of η′ precipitates in the stir zone were found, but chromium-bearing dispersoids remained nearly unchanged. The main particles in the stir zone and heat-affected zone were η precipitates as well as Guinier-Preston zones formed during post-weld natural aging. The small recrystallized grains were observed in the thermo-mechanically affected zone next to the stir zone. A W-shaped hardness distribution where soft region was produced in the heat-affected zone at a short distance from the stir zone were obtained. Hardness profiles of the welds were explained by precipitate distributions. Friction stir welding resulted in the reversion and coarsening of η′ precipitates. The formation of Guinier-Preston zones in the stir zone and some parts of the heat-affected zone during post-weld natural aging increased the hardness. In transverse tensile specimens, fracture occurred in a location with the minimum hardness at either advancing or retreating side randomly. Further, influences of welding parameters on mechanical properties were investigated. [ABSTRACT FROM AUTHOR]

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A new method for fast microstructure analysis of heavily deformed ferritic-pearlitic (F-P) steels has been developed based on X-ray diffraction (XRD). The method provides information about residual stresses and microstructure defects occurring within the material volume and therefore allows reliable estimation of strength properties. Besides, significant reduction of testing time can be achieved compared to conventional investigation methods. Development and testing of 'fast microstructure analysis' was done by means of experimental simulation of wire and rod production process including hot rolling, wire drawing, and heat treatment of steel C45 with ferrite/pearlite microstructure. It was found that the dominant structure defects driving the ultimate tensile strength of F-P steel in case of hot-rolled and heated steel are the misfit dislocations in pearlite, while in the cold-drawn wires, it is the residual stress borne by the cementite lamellas. [ABSTRACT FROM AUTHOR]

Aim Simplified adhesives are a blend of monomers with solvents that are expected to evaporate before light curing. The aim of the present study was to evaluate the effects of drying time and water storage on the ultimate tensile strength ( UTS) of three adhesives: Adper Single Bond 2 ( ASB), One- Step Plus ( OSP) and Clearfil S3 Bond ( CSB). Methods Dumbbell-shaped samples from each adhesive were prepared in three groups: (a) air drying prior to light curing; (b) no drying equal to active air drying; and (c) 3-h drying. Each group was further divided into two subgroups of no storage or 7 days' water storage, prior to the UTS measurement ( n = 10). Results Material, drying-time, and storage had a significant effect on UTS, and the interactions of the factors were also significant ( P < 0.05). OSP showed a higher evaporation rate under passive air drying, and OSP and CSB showed higher UTS values compared to ASB ( P < 0.05). Air drying improved UTS in OSP and CSB, but not in ASB. Likewise, water storage only affected the UTS of OSP and CSB. Conclusions The effects of air drying and water storage period on UTS are material dependent. Whenever solvent evaporation improved the UTS of adhesive, water storage decreased it. The all-in-one self-etching adhesive can maximize its best properties when the solvent is dried for an extended period. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effects of intracoronal bleaching on ultimate tensile strength (UTS) of sound and etched dentine and its ultrastructure morphology. Methodology Bovine dentine specimens with (e) or without previous etching with 37% phosphoric acid for 15 s were used for the intracoronal bleaching experiments. Teeth were randomly assigned to five treatments ( n = 10): (C) control – no bleaching, (SP) sodium perborate, (CP) 35% carbamide peroxide, (25% HP) 25% hydrogen peroxide and (35% HP) 35% hydrogen peroxide. Bleaching was performed four times within a 72 h interval and afterwards, dentine pulp chamber blocks were obtained. The blocks were sectioned in 0.7 mm-thick slices and these were trimmed to reduce the inner dentine to a dumbbell shape with a cross-sectional area of 0.8 mm2. Specimens were tested with the microtensile method (0.5 mm min−1) and data were analysed (two-wayanova-Tukey test, P < 0.05). Additional teeth were prepared for transmission electron microscopy (TEM) to evaluate dentine ultramorphology. Results The mean values of the UTS (SD) in MPa for sound dentine were: C = 48.3(8.5)a, SP = 34.6 (8.2)b, CP = 32.9 (8.9)b, 25% HP = 28.0(4.6)b, 35% HP = 26.4(6.6)b, and pre-etched dentine: Ce = 38.9(13.8)a, SPe = 31.3 (9.3)ab, CPe = 28.4 (6.2)ab, 25% HPe = 30.0 (7.9)ab, 35% HPe = 19.9(4.6)b. Significant differences between the means are indicated by the letters. TEM observations exhibited demineralization areas for all bleaching treatments. Conclusion Bleaching decreased dentine UTS after treatment. Pre-etched not-bleached dentine (Ce) presented UTS similar to pre-etched bleached dentine, except for 35% HPe. The decrease of UTS of bleached dentine could be attributed to ultrastructural alterations such as loss of inorganic components. [ABSTRACT FROM AUTHOR]

This research work aimed to find out the influences of the different amounts of chunky graphite on mechanical and fatigue properties of GJS 800 ductile cast iron. Chunky graphite has been a problem of heavy section thick-walled ductile cast iron components. Chunky graphite is branched and interconnected as a network within eutectic cells and has been observed to form in thermal centres of heavy ductile cast iron sections during solidification. This research work proved that chunky graphite in the microstructure decreases the ultimate tensile strength, the elongation to fracture and fatigue life significantly, but does not influence on the yield stress of ductile cast iron GJS 800 substantially. Low nodular count and nodularity rate also decrease the fatigue life of ductile cast iron, and the difference of fatigue life of specimens containing chunky graphite or having low nodular count and nodularity rate is not large. Influence of the amount of chunky graphite on fatigue life increases until 20% chunky graphite content, and above that the fatigue life does not decrease substantially. [ABSTRACT FROM AUTHOR]