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The bulk metallic glasses composites are a new class of bulk metallic glasses (BMGs), containing an amorphous metal matrix and reinforcing materials of metallic or ceramic nature in order to obtaining the desired combination of mechanical properties including strength, hardness, ductility and toughness. Composite materials of cylindrical form with the diameter of 10 mm and 5 mm in height were successfully prepared by hot-pressing of Zr – based glassy alloy powder and Fe – based nanocrystalline alloy powder in different volume fraction. The samples obtained were structural investigated by scanning electron microscopy and X-Ray diffraction and mechanically characterized by hardness and compression tests. It was found that increasing the volume ratio of the Fe-based nanocrystalline alloy up to a certain value leads to an increase in hardness and mechanical compressive strength.

Flame straightening is a technology process used to eliminate deformations. This method relies on local heating of the material to correct geometry or damaged parts. In the local automobile services its main use is for repairs of less critical deformed components. The maximum temperature and thermal gradient, heating time, cooling rate and number of heating cycles affect the mechanical properties since local heating can alter material microstructure. The aim of this research was to determine the mechanical characteristics of thin steel plates repaired by local heating associated with plastic deformation (similar to hot working) and cold straightening (similar to local cold working) for automotive side and door panels made of structural steel. Thin sheet plates, 0.9mm thickness, were deformed by impact and repaired by local heating using the flame and induction heating then plastically deformed while hot as well as straightened without heating. The heat repaired samples were studied by light microscopy to determine microstructure change and samples were tensile tested to determine their mechanical characteristics. Local excessive grain growth generates anisotropy, the assembly behaves as a composite material with regions that show significant plastic deformations while others little or no deformations at al. Without procedures adjusted to each material repairs involving heating are to be avoided, cold working should be employed when replacement is not possible.

This study comprises the studies performed on six in vivo failed centromedullary fixation devices, three made of stainless steel 316L and three of titanium alloy Ti-6Al-4V. Fractographic studies were performed using stereomicroscopy and scanning electron microscopy while metallographic studies were performed by light microscopy. Loading mode which caused failure was inferred based upon surface fracture topography and light microscopy studies were performed to observe if abnormal microstructures or inclusions could be the cause of the failure. In all cases the chemical composition was according to standard specifications and the microstructures appeared normal with low inclusionary content. The mode of failure was found to be fatigue and the crack initiation site was on the implant surface on roughness features and surface induced defects.

The aim of this study is to investigate the effect of alloplatic graft and platelet rich fibrin (PRF) , alone or in combination, on bone regeneration in Wistar rats femural defects. Bone defects were prepared in adults male of 20 Wistar rats. In a group of ten, the defect was filled with synthetic ceramic graft as an alloplastic graft; the others 10 were grafted with this alloplastic graft mixed with PRF. All animals were sacrificed on the 90th postoperative day and the femural bones were removed, histologic sections were prepared and the experimental sites were examined microscopically. Histologic examination revealed more new bone formation in the defects filled with alloplastic graft mixed with PRF than in the defects grafted with alloplastic graft alone. The platelet rich fibrin combination effectively induces new bone formation.

Most of the fixation implants for tibia fracture are made of various metallic alloys based on titanium or even stainless steel. But modern technologies and advanced materials offer endless opportunities of using polymers combined with various fillers to enhance and adjust mechanical properties in order to be as suitable and convenient for any patient.

Polylactic acid (PLA) is one of the most extensively used biodegradable aliphatic polyester produced from renewable resources, such as corn starch. Due to its qualities, PLA is a leading biomaterial for numerous applications in medicine as well as in industry, replacing conventional petrochemical - based polymers. The purpose of this paper is to highlight the mechanical properties, such as tensile stress, of pure PLA specimens in comparison with PLA based-composites, with three different added materials in PLA mass: Copper, Aluminum and Graphene, as well as the influence of filament angle deposition on these properties. In order to check if the the filling density of the specimen influences the ultimate tensile stress (UTS), three different filling percentages (60%, 80% and 100%) have been chosen in the experimental tests. In this context, the mechanical characteristics of four different filament types based on PLA material, starting from pure PLA to PLA with Aluminum, Copper or Graphene filler are compared. Understanding and controlling these parameters is essential for the successful use of PLA and PLA-based composites in different areas such as medical applications, sport equipments and light industry.These tests have been performed due to the fact there is a lack of information concerning the mechanical properties. In the scientific literature, such information is only available for expensive printing systems; for open source printers (as those used in these tests), the information is poor and for some new materials, even inexistant. According to the technical specifications, for an expensive printer the cost may exceed 3000 Euros, with a minimum layer resolution of 100 m, this type of printer can reliably reproduce many 3D objects accurately, in quiter conditions.

This work are made for determine the possibility of generating the specific parts of a threaded assembly. If aspects of CAD generating specific elements was analysed over time in several works, the technological aspects of making components by printing processes 3D through optical polymerization process is less studied. Generating the threaded appeared as a necessity for the reconditioning technology or made components of the processing machines. To determine the technological aspects of 3D printing are arranged to achieve specific factors of the technological process, but also from the specific elements of a trapezoidal thread or spiral for translate granular material in supply process are determined experimentally. In the first part analyses the constructive generation process of a spiral element. In the second part are identified the specific aspects that can generation influence on the process of realization by 3D DLP printing of the two studied elements. The third part is affected to printing and determining the dimensions of the analysed components. We will determine the specific value that can influence the process of making them in rapport with printing process. The last part is affected by the conclusions. It can be noticed that both the orientation and the precision of generating solid models have a great influence on the made parts.

The purpose of this study was to assess the accuracy of two 3D printed dental models manufactured after intraoral/IO and extraoral/EO scanning. A dental study model (KaVo Dental GmbH/Germany) was used as a reference for this research; this model was scanned with an industrial scanner (XT H 225 ST/Industrial CT scan/Nikon Metrology Inc./U.S.A.) and a reference STL file was generated (coded M1). Two 3D printed models (Form2/FormLabs Inc./U.S.A.) were produced via IO scanning (TRIOS 3 Battery Cart/3 Shape/Denmark), respectively via EO scanning (Swing Dental Scanner/Dof Inc./South Korea) of the reference dental model. The 3D printed models obtained were scanned with the industrial scanner, resulting in other two STL files (coded M2, respectively M3). All the STL files obtained (reference M1; M2; M3) were compared in pairs, using a 3D analysis software. Good results were achieved in obtaining 3D printed dental models via IO or EO scanning, yet, the 3D printed dental model obtained via IO scanning (M3) showed slightly improved dimensional compatibility with the reference model (M1) in comparison with the 3D printed dental model manufactured via EO scanning (M2).

In recent years, in many areas of civil engineering applications, fuzzy logic models have been used. The aim of this paper is to develop a fuzzy logic model to predict the adhesion stress in polymer concrete. Availability of experimental data was required to develop the relationship between the mixture variables of polymer concrete and its measured properties. The basic parameters considered in this study were epoxy resin, silica fume, aggregate sort I and aggregate sort II dosage. Using Mamdani fuzzy model, with the said parameters, we effectively predicted the adhesion stress in polymer concrete accurately by taking into account the parameters of the problem. In these circumstances, data can be acquired in a short period of time without wasting material, with decreased design cost, all this without attempting experiments and thus saving time. This study showed that the model used has a good prediction and generalization capacity with acceptable errors.

The article presents the process by which, with the help of 3D printing technology, the piston of the differential injection device was produced using ABS material. It was made with fused filament fabrication (FFF) technology, and the smoothing process was used to improve the surface quality. The piston is part of a complex equipment for underground fertilization of agricultural crops.