Key Engineering Materials Vol. 841

Abstract: The main objective of this investigation is to reduce and eventually replace the use of non-biodegradable synthetic fiber. Bio composites have shown growth and has been used in the domestic sector, aerospace industry, circuit boards, and automotive applications over the past few years. Many types of natural fibres have been investigated to produce composite materials that are competitive with synthetic fibre composites. Jute is a natural fibre and is 100% bio-degradable and recyclable and thus environmentally friendly. Its properties include high tensile strength, low extensibility. This bio composite specimen has been fabricated with the help of hot press molding machine. The flexural and Tensile tests have been done according to the ASTM standards. The increasing awareness of global environmental and social concern and new environmental regulations have propelled the search for new composites that are compatible with the environment.

Abstract: The fatigue limit and fracture behavior of epoxy carbon fiber reinforced composites and hybrid composites were investigated. An aluminum foil and thin aluminum plate were incorporated with the carbon fiber to make the hybrid reinforced composites. Several specimens were prepared, and a series of tests were carried out to investigate the fatigue life and fracture behavior. Then the results were compared among epoxy carbon fiber reinforced composites and the hybrid composites. It is discussed whether the S–N curves shows almost the similar characteristics of these two types of hybrid composites or not. As far as the present result, the stress ratio and the type of hybrid composites effect on the fatigue life. The interfacial bonding plays an important role in the strength and fracture behavior of notched specimen of the fabricated composites.

Abstract: The paper is aimed to the study of the corrosion-fatigue behavior of high strength steels for offshore pipelines. Tests have been performed in order to study fatigue crack growth in synthetic seawater under cathodic protection. The tests have been carried out on three different steel grades from 65 to 85 ksi with tempered martensite and ferrite-bainite microstructures. The effect of stress intensity factor, cathodic protection potential and cyclic loading frequency is shown.

Abstract: In recent years, metal injection molding (MIM) has been adopted as a process of manufacturing a solenoid valve which is a component of an electronic fuel injector, and PB permalloy component has been commercialized. However, Ni that is an element of PB permalloy is expensive material, and it makes difficult to produce the injector component in low cost. To reduce the production cost, we can use Fe-Cr alloys, although there are few studies on Fe-Cr alloys by MIM process. In this study, Fe-Cr-Si alloy specimens were manufactured by MIM process and the magnetic and mechanical properties were investigated. From these results, we found that high performance Fe-Cr-Si alloy can be obtained by setting Si content to 3% and reducing Cr content.

Abstract: This paper focuses on a study conducted on laser welding of printed 316L parts that were produced with a selective laser melting process. Commercial sheet material was used as a reference for the printed 316L parts. The effect of heat treatment on joint properties, and on what stage of the process it should be applied, was studied with metallography and mechanical testing. Optical microscopy was applied to analyze the microstructure of the base material and the weld seam. Tensile testing was applied for determining monotonic strength of different structures. The printed base material showed higher strength, but lower ductility in comparison to the commercial sheet material. In the welded condition, tensile properties were impaired by the welding, but for the commercial sheet material, no clear effects were seen. The difference was hypothesized to be caused by the higher strength mismatch in the printed joints. For the welded structures, the best strength-ductility combination was achieved by heat treating the parts both before and after the laser welding.

Abstract: The effect of Metakaolinization on the thermal and physicochemical properties of Badau Belitung kaolin is presented. Calcination of Badau Belitung kaolin indicated that kaolin was transformed to metakaolin at temperature above 500°C. The metakaolin was characterized using X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) and Brunauer-Emmett-Teller (BET). The XRD diffraction pattern of the metakaolin was highly amorphous as a result of calcination effect on the raw kaolin. The FTIR spectra of the metakaolin produced showed that the material was thermally stable at temperature range of 500–700°C, whereas the specific surface area values of the raw kaolin and the metakaolin formed were increased with increasing calcination temperature from 500°C to 700°C.

Abstract: The effect of super-chilling at -2°C compared with ice storage at 0°C on flavor quality changes of turbot (Psetta maxima) was investigated. Changes in total volatile basic nitrogen (TVB-N), sensory attributes and volatile compounds were periodically examined for 20 days. Results demonstrated that super-chilling retarded the increases of TVB-N values and maintained better sensory quality compared to the ice storage. Additionally, GC-MS analysis showed super-chilling could more effectively maintain the characteristic volatiles responsible for fresh fish flavor and reduce the contents of putrid compounds such as TMA and acetic acid.

Abstract: . Natural fibers have been found to be an alternative resource for synthetic materials. Natural composites are found to be a one hundred percent bio degradable product. Natural composites are also found to be having a great strength to weight ratio. In this process, hybrid sisal and polylactic bio composites are reinforced together by using the hand layup method. The ratio of sisal and polylactic element is in the ratio of 1:1 that are subjected to a compressive force with simultaneous heating process. Tensile strength and Flexural strength are evaluated as per the ASTM standards. Results shown that the there is good improvement in polylactic acid based biocomposite due to good interfacial between fiber and matrix.

Abstract: Natural Fibre composites are being widely used as a replacement to non-bio-degradable polymer composites. The unavailability of proper processes to treat the natural fibres and the errors in fabrication result in less accurate mechanical properties. The accuracy that is obtained by machine-based processes is not possible in Hand layup method, which is employed in fabrication of natural fibre composites. Finite Element method packages which are specially intended in modelling composite structures give more accurate result of properties than experimental setup, by avoiding fabrication errors. This paper evaluates Impact energy and then the tensile strength, flexural strength of a sugarcane fibre GFRP reinforced polymer matrix both by conventional Hand Layup method and also by Finite Element method.

Abstract: The aim of this research was study the influence of the Deep Cryogenic Treatment (DCT) on the microstructure transformation and materials properties of beryllium copper alloy (CuBeZr alloy). Microstructure analysis such as size, shape and number of precipitates were studied by Optical microscopy (OM) and Scanning Electron Microscopy (SEM). Microstructure analysis showed that transformation into the rod shape precipitates appeared after the process. The dispersion of CuNi precipitates and CuNiZr precipitates in the ⍺ matrix after deep cryogenic treatment was found to be increased. The change in number of CuNi precipitates and CuNiZr precipitates led to an increase in hardness and wear resistance. The maximum increase in hardness of 11% was observed with 48 hours soaking time with a reduction in surface wear of approx. 60%.