Materials Science Forum Vol. 1122

Abstract: Casting is one of the most commonly used manufacturing method for geometrically complex product. Among the casting technologies, sand casting is often found in application. Beside the advantages of the sand-casting process, it also has a drawback that is often encountered, namely product defects. Product defects can be caused by a lack of attention to sand casting parameters. This work aims to minimize those defects, including porosity defects, shrinkage defects and incomplete defects by optimizing process parameters using the Taguchi method. The identified sand-casting process parameters include gating location, riser location, molding conditions and pouring temperature with each parameter consisting of 3 levels. This research using the fractional factorial L₉ (3⁴). Data processing is carried out by analysis of mean (ANOM) to obtain plot effects. The results showed that the optimal combination of parameters that resulted in shrinkage, porosity and minimal incomplete defects were at gating location level 2, riser location level 1, mold condition level 2 and pouring temperature level 3. The results of the comparison before and after optimization were an increase of 0.77, where previously it was 1.30 to 2.07 based on normalized data.

Abstract: Titanium Nitride coating has attracted much interest in increasing the hardness of aluminum alloys. This study aims to investigate the effect of Ar: N gas mixture and time on increasing the hardness of aluminum alloys using DC sputtering. Preparation of TiN thin films on aluminum alloy substrates using flowing gas mixture parameters and time. First, the layer of TiN was deposited on the sample with a gas mixture of 90Ar:10N; 80Ar:20N; 70Ar:30N; and 60Ar:40N (%) for 60 minutes. Then the optimum gas mixture that produces the highest surface hardness is used in the second process with time variations of 30, 60, 90, and 120 minutes. The results showed that the highest hardness was achieved in a gas mixture of 70Ar:30N and 60 minutes. The TiN phase formed on the aluminum surface was identified by XRD, while the surface morphology was observed by SEM. Compared with untreated samples, the hardness of treated samples increased significantly.

Abstract: The revolutionary method of solid-state joining technique has already attracted significant attention of advance welding and joining research community. The technique has been continuously developing for many alloy systems for similar and dissimilar joints. Recent research in these areas aiming to join complex dissimilar alloy pairs, composite, polymers, ceramics etc. This paper presents a study of friction stir welding between marine-grade aluminum alloy AA 5083 and HSLA steel, configured in a butt arrangement. The study investigates the evolution of Fe-Al series of intermetallic layer formation at the joint interface and its effective management to yield best joint efficiency. The FSW in the said alloy pairs yielded an 83.25% welding efficiency based on the aluminum alloy side strength. XRD analysis along with SEM examination revealed the formation of Al₁₃Fe₄ and Al₅Fe₂ as intermetallic compounds which was confirmed by the EBSD analysis. The obtained results are discussed in the paper considering the effect of the weld joint performance.

Abstract: In this study, the Al₂O₃ round bar and Al-Si12CuNi (AC8A) round bar were joined by friction welding. AC8A is a typical piston material treated by the heat treatment T6. The parameters of the joining condition are friction time and upset pressure. SEM observed the microstructure at the interface region of joined materials. 1) Judging from these photographs, the damages to the microstructures at the interface region of joined materials by upset pressure are more significant than those caused by friction time. 2) The relationship between the joint conditions and mechanical characteristics from three points of bending test results for the joint material specimens. 3) The residual stresses around the interface were measured by the Raman spectroscopy method. There is a possibility that the friction welding conditions are correlated to the residual stresses.

Abstract: This study explores the optimization of Micro Friction Stir Spot Welding (mFSSW) by investigating the influence of tool profiles on welding outcomes, using aluminum alloy AA1100 with a 0.42 mm thickness as the specimen material. Monitoring temperature and RPM during welding with thermocouples and tachometers, mechanical properties are assessed through tensile shear tests, microhardness measurements, and macrostructural observations. The findings serve as the basis for developing Neural Network models using Rapidminer software, marking a transformative development that positions Neural Networks as potent tools for optimizing welding processes, potentially leading to achieving optimal weld quality. The investigation also delves into three welding tool configurations – the two-stage pin, one-stage pin, and pinless mFSSW probes – highlighting their distinct impacts on tensile shear test values and overall welding quality. Notably, the two-stage pin configuration emphasizes the significance of larger pin diameters and controlled heat generation for enhanced weld strength, while the one-stage pin configuration underscores the pivotal role of pin diameter and elevated temperatures in improving weld quality. The pinless mFSSW probe configuration, on the other hand, emphasizes the importance of shoulder diameter and temperature control for superior tensile shear test results. Leveraging Neural Network modeling for optimization, this study advances our understanding of parameter interactions and underscores the efficacy of Neural Networks in achieving superior tensile shear test values and welding quality in mFSSW, offering valuable insights for future endeavors in the field..

Abstract: Friction Stir Welding (FSW) is an innovative technique that enhances the conventional method of joining metals. Notably ecofriendly due to its energy efficiency, FSW involves minimal energy input, reduces pollution, and saves time and costs. It finds applications in diverse sectors such as automotive, aerospace, and industry. Each material requires specific process parameters, which leads to this study focusing on identifying suitable parameters for AA7075 aluminum with a 6mm thickness. Using a tool featuring a tapered cylindrical thread pin and a flat shoulder, the study aims to investigate the influence of FSW process parameters, rotation speed, and traverse speed on the mechanical strength of butt joint connections. The study's experimental design varies these parameters and evaluates the joints through tensile strength testing, hardness testing, and macrostructural analysis. Utilizing Response Surface Methodology (RSM), the data highlights the impact of rotation and traverse speed on tensile strength. Hardness test results present variations within heat zones, analyzing the effects of the mentioned variables. The findings demonstrate minimal flash and successful surface outcomes but also identify wormholes within the stir zone (SZ). Tensile strength testing reveals a definite correlation between RPM and traverse speed with joint strength. In contrast, hardness testing indicates that these parameters do not significantly affect joint hardness. Macrostructure examination suggests RPM and traverse speed have negligible effects on the heat-affected zone. In conclusion, FSW presents a sustainable and effective welding approach with implications for multiple industries, and this research provides insights into optimizing its parameters for specific aluminum materials.

Abstract: Cassava starch bioplastics have been known well as an alternative plastic replacing conventional petrochemical plastics, which have difficulty degrading rapidly in the environment. Cassava peels as waste is a potential eco-friendly starch source for biodegradable plastic. This study investigated the effect of graphene as a nanofiller on the hydrophobic properties of cassava peel starch film. Bioplastic was synthesized using the melt blending method by adding graphene in various amounts, which were 3 wt%, 5 wt%, and 7 wt%. Graphene was found to be able to increase the contact angle of the films up to 93° with the addition of 5 wt%. Graphene also affects water absorption properties. These results indicate that the hydrophobic properties of cassava peel starch films could be modified by adding graphene nanofiller.

Abstract: The study examined the properties of bleached Schoutenia ovata Korth Fiber (SF) for prospective application in composite reinforcement. .The characterization of SF was done using FTIR and SEM-EDS techniques to examine the morphology of SF following treatment with NaOH and various concentrations of NaClO. The treatment improved the interaction between the fiber and the composite matrix. As a result, fibers require bleaching before they may be processed further.

Abstract: In order to enhance diverse composites and foster sustainable development, it is essential to use strategic measures. Microcrystalline cellulose (MCC) has the desirable characteristics of being both renewable and biodegradable. The characteristics above provide MCC with a favorable option for enhancing the structural integrity of composite materials. This study examines the literature on using MCC as a composite reinforcement to identify its primary characteristics. This evaluation explores the properties and potential future advancements of the naturally derived materials under investigation. This work comprehensively reviews scientific publications to guide future research efforts. Based on empirical investigations, using MCC as a composite reinforcement has enhanced various mechanical and tribological characteristics. This study provides a comprehensive reference for implementing sustainable MCC as a composite reinforcement.