Key Engineering Materials Vol. 975

Abstract: In this paper, a series of tensile testing on wire drawing SUS 304 were conducted in order to meet the required specifications, thus, it can be utilized on the aircraft fighter components to remain stable and avoid shaking or vibration when the engine is operated. The studied material is expected to be used on flank airframes to improve its strength, wear resistance, corrosion, and aesthetic appearance. Series of tensile test has been conducted with universal testing machine (1 tonne) with modified jig configuration according to ASTM E8. The specimens were made according to the manufacture requirements such as wavy pin and straight pin connecting rod. The wire diameter has been drawing into the final diameter, which is Φ8.0 mm. From the tensile tests, yielding 1165.8 MPa and 1588.1 MPa, respectively. It is observed that the strength of woven SUS 304 wire drawing has reached the required specification to be manufactured in aircraft fastener. Factor of safety up to 2.0 has been acquired to the studied woven SUS 304 wire drawing.

Abstract: Welding joint Austenitic stainless steels can undergo intergranular corrosion attack in some service conditions, such as oil refineries, petrochemical plants, and industrial furnaces operating at high temperatures (between 500°C and 675°C). This research focuses on fabricating dissimilar metal welds to avoid failure due to sensitization and investigate stress-relieved carbon steel by Post-weld heat treatment (PWHT). This work studies a dissimilar weld joint (DWJ) of ASTM 335 grade P11 joint to ASTM 304L and PWHT after welding. These welding processes are used in multi-pass gas tungsten arc welding (GTAW) using filler metal R309L. PWHT at temperatures of 550 °C with holding times of 40, 50, and 60 minutes and then slow cooling in atmospheric air temperature, It was used to compare the results holding time carbon steel ASTM A335 Gr. P11 while processing. Holding time at 50 minutes has the maximum result of PWHT with 182 HV and has a good distribution of perlite with fine grain and increasing holding time also increases formed carbide on the grain boundary of stainless steel 304L.

Abstract: Nanoparticle addition into a fluid can increase the thermal conductivity. Such fluid is commonly called a nanofluid. Due to its improved heat transfer characteristic, nanofluid is widely used as coolant in engine or electronic equipment. In the steel heat treatment industry, nanofluid can be utilized as a quench medium. By controlling the amount of nanoparticle added in the nanofluid quench medium, the cooling rate can be adjusted. To preserve the heat transfer effectivity, the stability of the nanoparticle become very important. Hence, surfactant is quite essential to improve the particle stability and avoid particle agglomeration and sedimentation. In this study, a multiwalled carbon nanotube (MWCNT) was used as the nanoparticle in the distilled water. The concentration of the MWCNT was varied at 0.1, 0.3, and 0.5 % w/v. For the surfactant, Cetyl Trimethylammonium Bromide (CTAB) was chosen to disperse the particle better. In each of the three MWCNT variations, CTAB was added from 3 – 30% w/v. The maximum thermal conductivity obtained was in the nanofluid with 0.3% MWCNT and 5% CTAB at 0.72 W/mK. For the steel hardness, the value was roughly stable at 33 – 35 HRC in the nanofluid with no CTAB and 3 – 5% CTAB addition. Excessive surfactant addition at 30% CTAB decrease the hardness significantly up to 17 HRC.

Abstract: A powder metallurgical process has been applied to synthesize the FeNiCr+Y₂O₃ oxide dispersion strengthened (ODS) alloys. The composition of the reinforcing Y₂O₃ added into matrix was varied from zero to 2.0 percent weight. Raw powders were carefully weighed with a four-digit balance. Y₂O₃ powder was pre-linked into Fe powder as the dominant element in the matrix by manually ground for half an hour. Ni and Cr powders were then mixed evenly for the next a half hour to obtain FeNiCr+Y₂O₃ precursor. Avoiding agglomeration and grain coarsening, the precursor was uniformly homogenized by milling for 20 hours. The precursors were then compressed at an isostatic pressure of 100 kN to 12 grams of pellets each. To prevent sample erosion during smelting with an electric arc furnace (EAF), crystal growing mechanism by conventional sintering was performed at 900 °C for 2 hours. This strengthens the bonds between precursors in forming ODS alloys. The samples were then melt-casted in the arc by 4 times flips. As a result, the neutron diffraction analysis and SEM-EDS strongly reveal the austenitic crystal structure and Y2O3 oxide successfully dispersed in the cast-alloy respectively. The microstructures with Y2O3 oxide spread uniformly overall the cast-alloy surfaces.

Abstract: Innovation in the automotive field is now growing rapidly. New materials are considered to be incorporated in automotive design if they have economic and vehicle performance benefits. This research investigates the change of the Magnesium (Mg) addition and heat treatment to the mechanical properties and microstructure of the car chassis prototype with Al10Si Aluminum alloy base material. The process of casting using the High-Pressure Die Casting method. Variation of Mg (3, 4, 5 wt%) to increase the strength of mechanical properties of Al10Si aluminum alloy material. In the casting process, the first Al10Si heated up to 690°C. Mg is incorporated into the heating furnace, then stirred by a mechanical stirrer. Stirring speed of 90 rpm and stirring time of 120 seconds. After it has poured into the mold, the casting temperature is 740°C. Then cools the room to room temperature 39°C. Then performed, heat treatment, using the method of age hardening and artificial aging. The test results prove that the hardening heat treatment makes the grain size smaller. Small grain size, then increase the strength of the material with the addition of Mg elements.

Abstract: Aluminum materials are used in a wide field for household appliances, aircraft, cars, ships, and construction. This research aims to obtain a new material based on aluminum magnesium silicon (AlMgSi) alloy as an alternative material to replace the steel base material in the shaft propeller product. In this paper, we will use the die-casting method to investigate corrosion resistance and the microstructure of the propeller shaft with AlMgSi aluminum alloy base material. The main base material used is 6063 aluminum alloy, with variations in the addition of Si (1, 2, 4 wt%). Alloy Al6063 is heated to a temperature of 720°C to reach a complete liquid state. Then the temperature is lowered to 645°C, then the Si element is inserted into the heating furnace and stirred. Then the temperature is lowered to 615°C, then the Mg element is added, then stirred thoroughly by a mechanical stirrer. The rotational speed of the stirrer is 70 rpm and the stirring time is 240 seconds. They were then heated to a pouring temperature of 680°C. The mold is heated to a temperature of 265°C. Then poured into the mold and pressed 7 MPa. The cast is cooled at room temperature. Then the casting products were heat treated with a solution treatment temperature of 485°C for 3600 seconds and quenched. After that, the casting products were treated with artificial aging. The results of this study show corrosion resistance increases along with the addition of variations of Silicon. The highest corrosion rate was obtained by adding Si as much as 4 wt% of 511.28 mm/y. With the addition of variations of Silicon 0 wt%, 1 wt% and 2 wt% showed the corrosion rate of 173.35 mm/y, 201.60 mm/y, 233.49 mm/y. The microstructure shows differences in grain structure. materials with variations of si 0 wt% and materials with variations of si 0 wt%, 1 wt%, 2 wt% and 4 wt% have different grain sizes. The intermediate phase (Mg₂Si) was mostly formed at Si 4% wt variation. So this study proves that adding silicon elements can increase grain sizes and refiner the propeller shaft.

Abstract: This study presents a research paper on the influence of heat treatment on FSW in Al 7075 materials. A comprehensive investigation was used to examine the impact of crucial weld parameters on the weld quality, including strength, flexibility, corrosion resistance, and weld structure. Additionally, the influence of temperature and tempering time on the weld quality was thoroughly examined. A series of comprehensive experiments were carried out on a 2.5 m thick aluminum 7075 plate that was welded using the Friction Stir Welding (FSW) technique. The primary objective of these experiments was to methodically examine the impact of heat treatment on the welded plate's mechanical and microstructural characteristics. The samples underwent examination both before and during heat treatment. The macroscopic and microstructural characteristics were analyzed utilizing optical microscope, tensile testing, and microhardness assessment. The impact of heat treatment is noteworthy as it substantially reduces the weld hardness while enhancing its elasticity.

Abstract: Rotary friction welding (RFW) is one of the most essential creations of modern technologies because it satisfies and compensates for the shortcomings of traditional welding methods. This paper presents a study on the impact of the annealing solution process on the joints of the rotary friction welding process in Al 6061 material and with a selection of the best parameter for the procedure. The quality of the weld-joints was evaluated by a series of experiments of measuring hardness, tensile strength tests and observing the micro-structures of the specimens to achieve conclusive evidence. The aim of these experiments is to carefully and precisely examine the impact of the heat treatment process on the welded joints’ physical properties and microstructure properties. The results show that the heat treatment does enhance the mechanical properties of the material, but it is essential to conduct experiments to find the optimized parameters; or else, the properties will decrease largely.

Abstract: The allure of 4D printing and machine learning (ML) for various applications is unquestionable, and researchers are striving hard to improve their performance. In this work, machine learning has been applied to predict the tensile strength of the 4D printed materials. The study investigated the reinforcement of polylactic acid (PLA) filament with lignin from oil palm empty fruit bunches (OPEFB) in the presence of epoxidized palm oil (EPO) as 4D printable filament. The alkaline extraction method was carried out used sodium hydroxide (NaOH), followed by precipitation with mineral acids utilizing one-factor-at-a-time (OFAT). Thereafter, the tensile strength of the 4D printed material was evaluated by tensile testing machine followed by machine learning prediction in which convolutional neural network (CNN) was adopted. The morphology of the 4D printed materials was determined by scanning electron microscope (SEM). The SEM micrograph of the tensile test of biocomposites revealed layer-by-layer formation of the filaments on the printed unfilled PLA biocomposite indicating lower inter-filament bonding. In the first trial, the actual result of the experiment was evaluated to be 24.44 MPa while the CNN prediction was 25.53 MPa. In the second attempt, the actual result of the experiment was 31.61 MPa whereas the prediction from CNN was 27.55 MPa. The coefficient of determination value obtained from CNN prediction is 0.12662. The current study indicates that machine learning is an important tool to optimize and/or predict the properties of 4D printing materials.