Papers by Keyword: Tensile Properties

Abstract: TiB₂/7055 composite was synthesized by a new melt direct reaction from 7055-(Al-3B)-Ti system with ultrasound. The phase composition and the microstructures of the as-prepared samples were investigated by XRD, SEM and EDS. The result shows that no Al₃Ti phase is in existence. With the assistance of ultrasound, grains are significant refined. Moreover, the wettability between matrix and particles is improved. The shapes of TiB₂ particles are mainly hexagonal or near-spherical, and the size is about 500nm. TiB₂ particles are with uniform distribution. Compared with 7055Al matrix alloy, the tensile strength of the composite reaches 303MPa, increased by 10.2%. However, the elongation is 7.3%, decreased by 4.8%.

Abstract: Both open die and closed die powder compact forging can be used for the consolidation of Ti and pre-alloyed Ti 6Al 4V powders produced by a hydride-dehydride (HDH) process. The approach used is initial cold or warm compaction into cylindrical shapes, or into a specific pre-form shape appropriate for achieving a particular final forged shape. The economic benefit is near net-shape processing with minimum machining required after forging. Manufacturing costs are also minimised by forging a compact, with a sufficiently high enough density, in air, without a protective atmosphere. The challenge, from a manufacturing point of view, is the operation of a manufacturing route which gives rapid and qualified compaction to meet production demands and batch sintering to achieve a high enough density prior to final forging to shape. In addition to this the final product has to have the right level of mechanical properties. This paper reviews some key findings from powder compact production, through to sintering and forging. These will be presented in terms of alpha-beta phase distribution in the microstructure, the degree of porosity, heat treatment and their effects on mechanical properties.

Abstract: SiO_2f/SiO₂ composites reinforced with 3D six-directional preform were fabricated by silicasol-infiltration-sintering method. To characterize the mechanical properties of the composites, mechanical testing was carried out under various loading conditions, including tensile and shear loading. All of the testing curves exhibited highly nonlinear behavior. The results indicated that the 3D six-directional braided SiO_2f/SiO₂ composites exhibited superior tensile properties and good shear resistant. Therefore, the 3D six-directional braided composites developed can well meet the demands of the thermal structure component.

Abstract: Tensile test and morphology studies were performed to determine the influences of Trans-polyoctylene Rubber (TOR) as compatibilizer of NBRr filled ENR 50 with composition of 15 phr. Fine size (300μm-700μm) of NBRr was used as fillers. Both uncompatibilized and compatibilized NBRr/ENR 50 were prepared using two roll mill at room temperature with different php of 1.0, 1.5, 2.0, 2.5 and 3.0. It can be observed that tensile strength and modulus of elasticity were decreased as increased in TOR loading before started to increased at 1.5 up to 3.0. Meanwhile, the increment in the value of elongation at break when increased in the addition of TOR. The scanning electron microscopy (SEM) of the tensile surface fracture of increased TOR loading illustrated a better adhesion and dispersion in comparison of low amount of TOR loading.

Abstract: Effects of citric acid on the mechanical properties of thermoplastic tapioca starch/high density polyethylene/natural rubber (HDPE/NR/TPS) blends were investigated. The ratio between HDPE/NR was fixed at 70/30 and used as a matrix system. TPS loadings with and without modification with citric acid (CA) were varied from 0% to 30wt%. Mechanical and physical properties of blends were evaluated as a function of TPS loadings modified with and without CA. The tensile strength, Young’s modulus and elongation at break were found to decrease with increasing TPS content. However an improvement in the tensile strength for TPS modified with CA at 5%, 10% and 20% TPS loadings was observed. The degree of TPS adhesion and dispersion in HDPE/NR blends were determined by scanning electron microscope (SEM).Keywords; HDPE/NR/TPS, citric acid, tensile properties, morphology.

Abstract: Blends of styrene butadiene rubber/recycled chloroprene rubber (SBR/CRr) with and without of trans-polyoctylene rubber (TOR) were prepared and the effects of tensile and morphological properties were determined. Both uncompatibilised and compatibilised SBR/CRr blends were prepared using a two roll mill at room temperature with blend ratios 95/5, 85/15, 75/25, 65/35 and 50/50. Compatiblized SBR/CRr blends with TOR enhanced the tensile strength and M100 but reduced the E_b and rebound resilience compared to uncompatibilized SBR/CRr blends. The scanning electron microscopy (SEM) of the tensile fractured surface of compatibilised SBR/CRr blend at 15 and 50 blend ratios illustrated a stronger interfacial adhesion and better dispersion of CRr-SBR matrix.

Abstract: The effects on the properties of recycled latex glove (RL-G) filled Epoxidized Natural Rubber (ENR 50) were studied. Both compounds were prepared by two roll mill at five different compositions of RL-G (5, 15, 25, 35 and 50 phr). The size range of RL-G particles i.e., S₁ (300μm-700μm) and S₂ (3cm-5cm) were used. The properties such as tensile properties (tensile strength, elongation at break, and stress at 100% elongation) and morphology studies were determined. The results indicated that the both size, S₁ and S₂ of recycled latex glove filled ENR 50 blends exhibited an increased in tensile strength and elongation at break for increasing weight ratio of RL-G. Scanning electron microscopy (SEM) of the fracture surfaces shows that the fine size, S₁ RL-G/ENR50 exhibited high surface roughness and matrix tearing lines than the coarse size, S₂ thus improving the compatibility of RL-G/ENR50 compounds. The results overall indicated that the fine size, S₁of RL-G filled ENR50 contributed to the better properties such as tensile strength and surface morphology compared to the coarse size, S₂ mainly at 15 phr of RL-G content.

Abstract: The effect of recycled silicone catheter (rSC) on tensile properties (tensile strength, modulus at 100% elongation and elongation at break) and morphology of recycled silicone catheter filled epoxidised natural rubber (ENR 50/rSC) vulcanizates were studied in loading range of 0 to 50 phr with two different size; fine (300-600μm) and coarse (1-2 cm). For tensile properties, tensile strength, modulus at 100% elongation (M₁₀₀) and elongation at break (E_B) for both ENR 50/rSC fine and coarse vulcanizates show increment up to 15 phr but then decreased as the rSC content increased. Comparison between ENR 50/rSC fine and coarse vulcanizates indicates that ENR 50/rSC fine vulcanizates has better tensile properties than ENR 50/rSC coarse vulcanizates due to better dispersion and filler-rubber interaction as proven in morphological study. The results indicate that the morphology of ENR 50/rSC fine vulcanizate is better than that of ENR 50/rSC coarse vulcanizates in which fine rSC well bonded with ENR 50.

Abstract: Low density polyethylene (LDPE) and natural rubber (NR) filled silica composites were prepared by using internal mixer (Brabender) at 150°C and 50 rpm for 10 minutes. Silica was incorporated into polymer matrix by three mixing routes by using Brabender. In mixing I, filler was added into LDPE/NR blend. In mixing II, filler was added prior to LDPE, which was further compounded with NR. In mixing III, filled was pre-dispersed into NR using two-roll mill, after that the compound is blended with LDPE. The effects of filler incorporation routes on the morphological and tensile properties of prepared composites were studied. Observation from SEM result showed that silica tended to localize in NR phase than LDPE phase in the composite. In addition, silica filled LDPE/NR composite exhibited the highest tensile strength in mixing II and lowest in mixing III. Tensile fracture surface of the composites showed typical morphology of LDPE and NR phase depending on mixing methods. KEYWORDS: LDPE/NR, silica, mixing order, tensile properties, morphology

Abstract: Fused Deposition Modelling (FDM) of thermoplastic materials is generally a well-known technology among all additive manufacturing (AM) technologies and therefore, it is essential to investigate the mechanical properties of such FDM processed materials. Several open-source and low cost AM machines, known as 3D Printers, have recently been developed using thermoplastic extrusion process based on the original FDM technology. Many of these 3D Printers use Polylactic Acid (PLA) plastic for building parts. The main objective of this paper is to investigate the tensile properties of the PLA thermoplastic material processed by the Cube-2 3D Printer. In this study, the dog-bone sized PLA specimens are printed in different build orientations and a Zwick Z010 tensile testing machine is used to determine the tensile properties of PLA in different build orientation.