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This study aims to characterize a novel glass/epoxy architecture sandwich structure for electronic boards. Understanding the thermo-mechanical behavior of these composites is important because it is possible to pre-determine whether defined “internal” thick laminates will be suitable for embedding components in the direction of the axis “z,” i.e. this method of manufacturing multilayer laminates can be used for incoming miniaturization in electronics.

Laminates with a low glass transition temperature (Tg) and high Tg with E-glass type were treated, tested and compared. Testing samples were manufactured by nonstandard two steps unidirectional lamination as a multilayer structure based on prepreg layers and as “a sandwich structure” to explore its effect on thermo-mechanical properties. The proposed tested method determines the time and temperature-dependent viscoelastic properties of the board by using dynamic mechanical analysis, thermo-mechanical analysis and three-point bend tests.

This testing method was chosen because the main property that promotes sandwich structure is their high stiffness. Glass/epoxy stiff and thermal stabile sandwich structure prepared by nonstandard two-stage lamination is proper for embedding components and the next miniaturization in electronics.

Compared with by-default applied glass-reinforced homogenous laminates, novel architecture sandwich structure is attractive because of a combination of strength, stiffness and all while maintaining the miniaturization requirement and multifunctional application in electronics.

The fan-out wafer level package (FOWLP) becomes more and more attractive and popular because of its flexibility to integrate diverse devices into a very small form factor. The strength of ultrathin FOWLP is low, and the low package strength often leads to crack issues. This paper aims to study the strength of thin FOWLP because the low package strength may lead to the reliability issue of package crack.

This paper uses the experimental method (three-point bending test) and finite element method (ANSYS simulation software) to evaluate the FOWLP strength. Two theoretical models of FOWLP strength are proposed. These two models are based on the location of FOWLP initial fracture point.

The results show that the backside protection tape does not have the ability to enhance the FOWLP strength, and the strength of over-molded structure FOWLP is superior to that of other structure FOWLPs with the same thickness level.

There is ample research about the silicon strength and silicon die strength. However, there is little research about the package level strength and no research about the FOWLP strength. The FOWLP is made up of various materials. The effect of individual component and external environment on the FOWLP strength is uncertain. Therefore, the study of strength behavior of FOWLP is significant.

This study aims to systematically compare the effect of increasing fiber–matrix interface adhesion and matrix toughness in layered composite materials.

Silane ((3-glycidyloxypropyl) trimethoxysilane) was applied to strengthen the fiber–matrix interface connection in e-glass/epoxy laminated composite material. Using a cationic surfactant, 0.1% multi-walled carbon nanotubes (CNTs) were added to the matrix in two different ways, by with and without chemical functionalization using the vacuum infusion method.

In the results obtained from the three-point bending test specimens, it was determined that the synergistic effect of silane application and non-functionalized CNT in the matrix was higher in terms of flexural modulus and strength values.

The functionalization of multi-walled CNT did not give the expected results because of reasons such as viscosity increase and agglomeration in the matrix.

In this study, a simple model for normalization and prediction purposes was developed, which allows the determination of the flexural modulus and un-notched flexural strength values from one test result of the notched specimen. A systematic comparison was performed by varying each parameter in the composite material.

Fracture properties of concrete are mainly influenced by specimen shape, size and type of testing method. The study aims to identify the characteristic divergence in fracture – evaluating testing methods, i.e. three-point bend test and wedge splitting test for fibrous self-compacting concrete.

A total of nine mixes with three different coarse aggregate sizes (20, 16 and 12.5mm) and three coarse to fine aggregate quantities (40–60, 45–55 and 50–50) were considered to examine the influence of materials on fracture parameters of fibrous self-compacting concrete. For three-point bend test, size effect method was considered to analyze the fracture properties.

The experimental investigation revealed that fracture energy calculated from wedge splitting test was reasonably on higher side for maximum coarse aggregate-based specimens for all coarse to fine aggregate quantities, while for the size effect method, fracture energy value was maximum for least coarse aggregate sized specimens.

The fracture properties of fibrous self-compacting concrete obtained from wedge splitting test method was higher than the size effect method. This is due to the consideration of only peak load for determining the fracture properties in size effect method analysis.

This paper aims to evaluate the influence of molybdenum disulfide (MoS₂) concentrations (5, 7.5, 10, 12.5 and 15 Wt.%) on the microstructure and tribological property of the self-lubrication cubic boron nitride (CBN) abrasive composites.

Three point bending method and rotating sliding test are used to evaluate the flexural strength and tribological property of self-lubricating CBN abrasive composites. Microstructure, wear morphology of the ball and scratch are supported by scanning electron microscopy, optical microscope and three-dimensional confocal microscopy, etc.

The MoS₂ concentration has a significant influence on the interface microstructure between CBN abrasives and matrix alloys, and thus, affects the flexural strength of CBN abrasive composites. The grain fracture modes of CBN abrasive composites are transformed from the transgranular fracture into intergranular fracture as the MoS₂ concentrations increase. Additionally, the friction coefficient of as-sintered samples decreases with the MoS₂ concentrations. The MoS₂ concentrations of 10 Wt.% are final determined to fabricate self-lubricating composites in basis of the mechanical and lubricating property.

The ball is fabricated under vacuum sintering process. The tribological property of self-lubricating CBN abrasive composites is evaluated in terms of the friction coefficient and morphologies of the ball and scratches after rotating sliding tests.

The purpose of this paper is to improve the surface finish and, therefore, the fatigue resistance of some endodontic files by electrochemical polishing; the influence of applying an autoclave’s sterilising cycle to the endodontic files under study was also assessed during the research herein presented.

In total, 22 Ni-Ti endodontic instruments of two sizes, namely, ref. Hyflex 0.04/20 and 0.06/20 (taper: 0.04; 0.06 and tip diameter: 0.20 mm, respectively), were submitted to rotational bending tests at 500 rpm; the radius and the angle of curvature imposed to the endodontic instruments during the experimental tests were equal to 4.7 mm and 45°, respectively. In addition, 18 endodontic files (out of the 22) were subjected to electrochemical polishing before in vitro fatigue tests had been carried out. Several combinations of electrochemical parameters were considered during the preliminary experiments involving electrolyte, voltage, flow rate and duration. The endodontic files under study were weighted using a high-precision balance before and after polishing, and mass variation was determined. Also, a sterilising cycle was applied to six polished endodontic instruments, which were placed inside an autoclave at 134°C, for 30 min, and under a pressure of 2.16 bar.

The fatigue resistance of as-received endodontic files ref. 0.04/20 is much larger (+480 per cent) than the fatigue strength of endodontic files ref. 0.06/20. The weight variation due to electropolishing was comprehended between 0.53 mg and 1.01 mg, and the fatigue resistance of all polished endodontic instruments increased between 30 per cent (0.06/20) and 80 per cent (0.04/20) when compared with the fatigue resistance of the as-received files. The application of an autoclave’s sterilisation cycle had a negative impact on the fatigue resistance of instruments ref. 0.04/20 and a positive impact on the durability of instruments ref. 0.06/20.

The application of an electrochemical polishing process increased the fatigue resistance of the endodontic files under study significantly, and the values for the variables of the electrochemical process were never published elsewhere. The surface finish improvement was obtained by immersing the endodontic files in a Struers’ Electrolyte (ref. E2) for 3 s while applying 30 volts and a flow rate of 1.

Direct additive manufacturing of ceramics (DAMC) is a highly promising ceramics preparation technology because of its simple process and rapid response capability, but the cracking issue prevents its industrial application. The purpose of this paper is to propose aluminum titanate (Al₂TiO₅) with low coefficient of thermal expansion (CTE) to suppress cracks during the DAMC.

Al₂O₃/Al₂TiO₅ (A/AT) composite ceramic samples with different compositions were in-situ synthesized from Al₂O₃/TiO₂ (A/T) powder in a directed laser deposition (DLD) process. The relationship between the content of TiO₂ and cracking characteristics of fabricated sample was discussed. Phase composition, microstructure and properties of the fabricated samples were also investigated.

The results of this paper show that the doping of TiO₂ can obtain Al₂TiO₅ synthesized in situ by reaction with Al₂O₃ and effectively suppress cracks during DAMC. When the content of TiO₂ reaches 30 wt.per cent, cracks hardly occur even under conditions of slow deposition. Crack-free structures such as vane, cone and pyramid were successfully prepared, with a maximum cross-sectional dimension of 30 mm and maximum length of 150 mm. A continuous matrix phase formed of the low CTE of Al₂TiO₅ is the major cause of crack suppression. The dispersed distribution of a-Al₂O₃ columnar dendrites has the effect of increasing the strength of the matrix. Under current process conditions, the prepared sample with 10 wt.per cent TiO₂ has micro-hardness of 21.05 GPa and flexural strength of 170 MPa.

This paper provides a new method and inspiration for direct additive manufacturing of large-sized crack-free ceramics, which has the potential to promote practical application of the technology.

The purpose of this paper is to study the influence of changing printing parameters (powder layer thickness and binder saturation) in a three dimensional printing machine (3DP) on the transformation of 3DP printed plaster of paris to hydroxyapatite by low temperature phosphorization.

Plaster of paris‐based powder mixture was used to print specimens using different powder layer thickness (0.080, 0.10 and 0.20 mm) and saturation ratio (1 and 2). Subsequently, density, microstructure, mechanical properties, transformation rate and phase composition were analyzed to compare the influence of such printing parameters on properties.

It was found that printing parameters strongly affect the transformation efficiency and properties of the samples. The sample printed at layer thickness of 0.10 mm and saturation ratio of 1 yielded the highest transformation rate, density and greatest flexural modulus and strength after conversion. This was related to the sufficiently low density structure with good mechanical properties of the as‐fabricated 3DP sample which was suitable for the low temperature phosphorization process. Hydroxyapatite and monetite were found to be the main phases after conversion and the content of each phase depended on the conversion time and on also the printing parameters.

The optimal printing parameters were true for the materials used in this study. In the case of using other materials formulation, the optimal printing parameters might be different from these values.

The results presented here can be used as a guideline for selecting printing parameters in 3DP machine for achieving properties as desired for specific applications or post‐processing techniques.

The paper demonstrates the printing parameters that were needed to be considered for efficient phase transformation and high mechanical properties.

A new kind of polymer mixture (co-PA-PES) was prepared in different mass ratios, by mixing polyether sulfone hot-melt adhesive (PES-HmA) and copolyamide B249 (PA-B249). This study aims to investigate its characteristics of laser sintering and get the optimal process parameters.

The effect of mass ratio of co-PA-PES on thermal behavior was analyzed using a simultaneous thermal analyzer, and the density and mechanical properties of sintered parts were tested to evaluate the performance of the polymeric system. Scanning electron microscopy and Fourier transform infrared spectroscopy were performed to characterize the microstructure and binding mechanism of sintered co-PA-PES parts. Specifically, mechanical properties of the mixture with 20 Wt.% PA-B249 were optimized based on a design of experiment methodology, along with the restriction of maximum absorbable laser energy density.

Liquid phase fusion was considered as the main sintering mechanism for co-PA-PES, and mechanical interlocking was the dominant binding mechanism. The effects of mass ratios of this material on the thermal properties, density and mechanical properties were obtained via data results. Additionally, compared to neat PES-HmA, co-20 Wt.% PA-PES showed a 71.7 per cent increase in tensile strength, 24.4 per cent increase in flexural strength and 102.1per cent increase in impact strength.

This paper proposed a new kind of polymer mixture as the feedstock for laser sintering with the advantages of low price and easy processing. The filler of PA-B249 effectively improved the performance of the polymer mixture, including but not limited to mechanical properties.

This paper aims to investigate the resultant optimal ultimate tensile strength, elongation, flexural strength and modulus, compression strength and impact strength of fabricated alkali-treated Lagenaria siceraria fiber (LSF)-reinforced polymer matrix composite by optimizing input factors and microstructural characterization by influencing fiber length, fiber concentration and treatment condition of LSF.

The fabrication of LSF-reinforced composite specimens involved surface treatment followed by custom experimental design using a simple hand layup process. The wear analysis was performed by a multi-tribotester TR25 machine, and the developed model was validated by using statistical software Design Expert V.8 and analysis of variance (ANOVA). The surface morphology of the sample was also analyzed by field emission scanning electron microscopy.

The alkali treatment for LSFs had reduced the hemicellulose, and enhanced mechanical performance was observed for 30 wt.% concentration of L. siceraria in epoxy resin. Thermogravimetric analysis revealed thermal stability up to 245°C; microstructure revealed fiber entanglements in case of longer fiber length and compression strength reduction; and the surface-treated fiber composites exhibited reduced occurrences of defects and enhanced matrix–fiber bonding. Enhanced mechanical performances were observed, namely, ultimate tensile strength of 17.072 MPa, elongation of 1.847%, flexural strength of 50.4 MPa, flexural modulus of 3,376.31 GPa, compression strength of 52.154 MPa and impact strength of 0.53 joules.

The novel approach of optimizing and characterizing alkali surface-treated LSF-reinforced epoxy matrix composite was explored, varying fiber length and concentrations for specimens by empirical relations and experimental design to obtain optimal performance validated by ANOVA. Enhanced properties were obtained for: 7 mm fiber length and 30 wt.% concentration of fiber in the composite for alkali-treated fiber.