Papers by Keyword: Fractured Surface

Abstract: As the largest sago starch producer in the world, Indonesia has a very large amount of leftover waste from sago starch production, which is usually called sago pith waste (SPW). This large amount of waste has enormous potential to be utilized for other benefits and purposes. In this study, SPW was tested for use in manufacturing composite materials. The aim is to investigate the detailed properties of the composites that have SPW particles in them. Unsaturated polyester resin was used as the composite matrix, and three different SPW percentages were tested: 20%, 30%, and 40%. Tensile tests were performed on the composites, and three specimens were prepared for each SPW percentage variation. All nine specimens tested failed at the maximum given load. Either the maximum strain before the specimen failed or the ultimate tensile stress decreased with larger SPW percentages used in the composites. Further, SEM micrograph examination of selected fractured specimens successfully revealed the behavior and the morphology of SPW particles on the fractured surface.

Abstract: Sago starch, amylose and amylopectin were used as fillers in natural rubber (NR) latex compounds. The compound was prevulcanized at 80 °C until chloroform number 2-3 was achieved. The effect of the fillers on the NR latex film mechanical properties (tensile properties and tear strength), and crosslink density were obtained. The fractured surface of the films was captured via scanning electron microscope (SEM) Zeiss Supra 35 VP. The results shown the addition of fillers reduced the tensile strength and elongation at break of the NR latex films but increased in the films tear strength. The swelling index of the films increased, indicating lower crosslink density possessed by the polysaccharide filled films. From the SEM micrograph, the addition of sago starch and amylose produced an uneven freeze fractured surface similar to the control starch films. Meanwhile, for films reinforced with amylopectin, the smooth surface is obtained indicating poor interfacial adhesion between filler and NR latex matrix.

Abstract: Nanocellulose (NCC) is incorporated into nitrile butadiene rubber (NBR) latex with the composition 0 to 5 phr using dipping method. Mechanical properties of NBR/NCC composites using tensile test was used to characterize their mechanical performance and the fracture surfaces post tensile test were studied. The tensile strength of NBR/NCC composites increase significantly with the addition of nanocellulose. This could be anticipated due to the presence of Van der Waals interaction between hydrophilic natures of nanocellulose with hydrophobic of NBR consequently limits the tearing propagation. The result was supported with the fracture surfaces morphology viewed under Fourier Emission Scanning Electron Microscopy (FESEM).

Abstract: The SSRT behavior in hydrogen dissolved hot water was investigated for cold worked SUS316L at a strain rate of 5 x 10-7/sec. The cold work to 75% thickness reduction of the as-annealed steel resulted in the hardness increase from 150 HV to 420 HV. The tensile yield stress of the cold worked specimens (CW=75%) was about 1000 MPa and the total tensile elongation was significantly reduced from 0.8% of annealed specimen to 0.14% of the 75%CW specimen. The results of EPR tests on SUS316L steel indicated that the EPR-DOS increased with increasing sensitization period at 700°C and decreased with increasing degree of cold work or reduction in thickness. In the water with hydrogen dissolution of 0.4 ppm, many IGSCC type cracks were nucleated on the specimen side surfaces, while the fractured surface was almost TGSCC. No such a SCC as observed in hydrogen dissolved water was observed after the test in oxygen dissolved water. The susceptibility to SCC increased with increasing hydrogen content in hot water. Cold work caused the reduction of the number of surface cracks and disappearance of IGSCC.

Abstract: Large-sized Ti/Ti-Al micro laminated thin sheet with thickness of 0.12mm was prepared by high-power electron beam physical vapor deposition technology, and then tensile tests of specimen after hot-pressing densification were carried out at room and high temperature, and tensile specimen was examined the fractured surfaces by SEM and OM. It was found that the tensile specimen under room temperature presents a compound quasi-cleavage and intergranular fracture, and a certain plastic deformation of Ti toughening layer was detected during fracture process. Tensile fractured surfaces under high temperature present the feature of compound dimple models and quasi-cleavage, furthermore, the size and the quantity of dimple exhibited an enhancing trend with test temperature increased. Results show that the cracks will stagger along the inter-laminar interface or the layer due to which micro-laminate expresses a good characteristic of delayed fracture. The toughening mechanisms are that the crack deflection and micro-bridge connection caused by the toughening layers increases crack propagation resistance.

Abstract: Specimens of aluminum (Al), austenitic stainless steel (SUS304L), pure iron (Fe) and Oxygen-free high conductivity copper (Cu) were treated by argon ion bombardment, and then were bonded by diffusion bonding method. The effects of argon ion bombardment on diffusion-bonded joints of four kinds of metallic materials were compared from the tensile strength at real bonded area and the fractographs. The results showed that bonding temperature was lowered by argon ion bombardment treatment for four kinds of materials. The effect of argon ion bombardment on diffusion-bonded joint depended strongly on the chemistry of the surface to be bonded, and increased in Al, SUS304L, Fe, and Cu in turn.