Papers by Keyword: Tensile Properties

Abstract: Nickel-copper alloys are commonly used in highly corrosive conditions where strength is required. Typical applications are in the marine sector, petrochemical industry, or energy facilities such as chemical tubes, pumps, heat exchangers and superheated steam systems. This paper compares the microstructure and mechanical properties of a cast alloy with a 3D printed alloy processed via a laser powder bed fusion (LPBF) technique. Small cylindrical specimens were used for tensile tests at room temperature (RT) and elevated temperatures up to 750 °C in air. The tensile stress-strain response was determined for both types of materials. At RT, LPBF material has a higher yield strength and ultimate tensile strength than a cast alloy. At elevated temperatures, the strength of both variants is comparable. However, the fracture elongation of the LPBF material is significantly lower over the entire range of investigated temperatures. Fracture surfaces and polished sections parallel to the specimen axis were investigated to compare the microstructure and damage mechanisms of the nickel-coper alloy 400 prepared by conventional casting and via LPBF.

Abstract: The present work investigates the effect of surface treatment of ground tire rubber (GTR) waste on the tensile properties of GTR /epoxy composites. The GTR was treated using 10 wt% alkali solution and 1 wt% stearic acid in acetone. It was found that the treated GTR decreased the tensile strength, about 4.8 and 2.9% for NaOH-and stearic acid-treated GTR, respectively, compared to the untreated GTR. Nevertheless, the treated rubber increased the elastic modulus of the epoxy composites, about 5.2 and 9.3% for the NaOH-and stearic acid-treated GTR, respectively, compared to the untreated GTR. The strain at break and the absorbed energy of the treated GTR/epoxy composites were lower than the untreated GTR, consistent with the increase of elastic modulus for the treated GTR. Scanning electron microscopy revealed that the bonding of the stearic acid-treated GTR-matrix was good, indicating better interfacial strength than the untreated and alkali-treated GTR-epoxy matrix.

Abstract: This article focuses on the production of tensile test (ASTM D638-03) specimens using fused deposition modelling technique as preliminary study for preparation of 3D-printed SUAV wings. Carbon-PLA (nylon 6/66 copolymer adding with 20% of carbon fiber) was used as 3D filament. There were 7 printing orientations: 0^o, 15^o, 30^o, 45^o, 60^o, 75^o, and 90^o based on tensile axis with 3 specimens for each direction (21 specimens in total). Printing parameters were set using open-source slicing application CURA. It was found delamination and fracture outside the gauge length causing high deviation of the mechanical properties value. So, the result of the testing test seems like do not comply with theoretical aspect of relationship between fiber orientation and tensile properties of composite materials. Taking care of printing parameters and increasing the number of specimens has an opportunity to achieve high precision results since precise data is crucial as a starting point for the development of SUAV wings.

Abstract: Fiber pre-stress composites are used nowadays in many applications that need extra strength without adding more reinforcements. Nano graphene platelets are selected to be added to the composite as it has high tensile properties. This work studied the effect of adding Nano graphene platelets with different weight ratios of 0.5%,1%, and 2% to the resin during the curing process in the presence of fiber pre-stressing of 1MP and 2MPa. The results show improvement in most properties of composites like tensile strength, modulus of elasticity, flexure strength, and modulus of flexure with the ratio of (43-57%),(35-55%),(100-134%), (60-90%) respectively. A numerical model was built to simulate tensile and flexure tests using ANSYS software. The divergence between the experimental and numerical results did not exceed 5%. Adding Nano graphene with a weight ratio of more than 2% will have a negative effect on the properties as the Nano graphene will agglomerate and lose most of its high properties that match with most literature reviewed.

Abstract: This work aims to study the mechanical properties and microstructural characteristics of rotary friction welding of the unsymmetrical (plate/rod) joints of AISI 1018 low carbon steel plate and AISI 1020 low carbon steel rod. The mechanical properties (tensile properties and hardness) were studied. The fractured surface of the tensile specimen was examined by Scanning Electron Microscope (SEM). The tesnile properties (strength and elongation) are higher than the AISI 1018 plate but slightly lower than the AISI 1020 rod due to coarse ferrite grains in the HAZ region of the AISI 1018 plate. The hardness varied from the fully deformed zone (FDZ) to the base metal. The average value of the ultimate tensile strength of the friction welded joint is about 452 MPa. The average value of hardness at fully deformed zone is about 252 Hv, which 32% higher than the base metal.

Abstract: The synthesis of dinickel boride (2.5 wt.% and 7.5 wt.%) reinforced with titanium matrix was achieved using the spark plasma sintering. The characterization of the sintered samples was investigated with an X-ray diffractometer (XRD), Optical microscope (OM), and Scanning electron microscope (SEM). The OM and SEM images of the sintered samples revealed lamellar structures with particle distributions. The relative densities of the sintered samples increased from 94.3% to 97.3%, while the microhardness values increased from 181 HV1 to 275.2 HV1 due to the addition of Ni₂B particles. Furthermore, the tensile properties of the sintered composites decreased with increasing Ni₂B contents. The addition of Ni₂B particles increased the wear resistance of the fabricated samples. The fractography of the sintered composite showed ductile and brittle failures.

Abstract: This work is concerned the tensile properties of the secondary Ni-based single-crystal superalloy DD6 near [001] orientation at 760°C. In this study, anisotropic tensile properties of DD6 alloy within 10° of the [001] orientation were exhibited at 760°C. The yield strength and ultimate tensile strength of DD6 alloy oriented close to [001] direction was the highest. As the deviation off the [001] orientation increased, both 0.2% yield strength and ultimate tensile strength was decreased. The specimens oriented close to [001]-[111] boundary exhibit higher yield strength and ultimate tensile strength than the specimens oriented close to [001]-[011] boundary. Numerous of dislocations can be found in the γ matrix channels during the tensile deformation. A number of dislocation pairs and few of stacking faults are found in the γ' precipitates after the tensile at 760°C. The morphology of γ' phases in DD6 alloy maintained cubical during the tensile deformation at 760°C. With Schmid's Law, the mechanism of anisotropic tensile properties in DD6 alloy near [001] orientation is analyzed.

Abstract: In this current article, an effort was made to briefly study the impact of magnesium content on the mechanical and metallurgical performance of as-cast Zn-Al-Si-Mg alloy. Zinc, aluminium, and silicon of appropriate weight quantities were melted in an electric furnace, and magnesium of varying quantities (1-5wt%) was added to the melt to obtain rectangular cast specimens. Microstructural, hardness and mechanical property analysis was conducted for the developed alloy in the as-cast condition. It was noted that an addition of Mg to the Zn matrix refines the grains but more than 3wt-% of Mg to the matrix forms clusters which deteriorate the property of the alloy in the as-cast condition. The value of hardness and tensile strength were noted to enhance, and ductility was observed to decrease from the baseline alloy to the alloy with 3wt% of Mg. Further addition of Mg decreased the properties of the alloy.

Abstract: Plastic waste disposal is among the most challenging problems of the current era. Therefore, new methods and applications for the utilization of waste plastics are increasingly needed. To find them, it is essential to research and develop the material properties of recycled plastics. The effect of different ultraviolet light (UV) stabilizers on the color stability, melt properties and tensile properties of mixed waste plastics blends was studied in this paper. The mixed waste plastics collected from two different waste sources were prepared as specimens by injection molding, and studied with two different types and loading amounts of UV stabilizers. UV absorbers (UVAs) and hindered amine light stabilizers (HALS) were used as UV stabilizers. A specimen produced without the addition of a UV stabilizer was used as a reference specimen of both the blends. After the accelerated weathering, the addition of a UVA provided an improved, smaller change in color than the addition of HALS. Among the tensile properties, the addition of UV stabilizers clearly improved the tensile strength and tensile modulus for almost all the studied specimens. Additionally, the melt properties of both the studied plastic blends were found to be increased by the addition of UV stabilizers.

Abstract: Retracted article: In this study, the influence of silane coupling agent on the matrix/ fiber interface bonding and its effect to the mechanical properties of oil palm frond fiber reinforced polyester composites were investigated. Tensile and flexural properties of the composites were studied at 0 - 10.2 volume fraction (% fiber content). Results showed an increasing trend in tensile modulus while tensile strength and flexural strength reduced as the fiber content increased. Higher tensile modulus values were observed in silane treated fiber composites due to additional fiber/ matrix interaction and increment in polyester molecular chain mobility constraint. Reduction in tensile strength is caused by decrease in the matrix crystallinity and formation of stress concentration spots emerging from interface discontinuity. These obstructions, however, were reduced by fiber surface modification, which improved the tensile strength. Enhanced fiber dispersion upon surface modification was unveiled through scanning electron micrograph images.