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PENGARUH UNSUR TEMBAGA (CU) TERHADAP FLUIDITAS PADUAN AL-SI 11.8 WT% (ADC 12) DENGAN METODE VACUUM SUCTION TEST Suharno, Bambang; Nanda, Is Prima; Arifin, Bustanul; Seto, Demas
Jurnal Energi Dan Manufaktur Vol 1, No.2 Desember 2006
Publisher : Department of Mechanical Engineering, University of Udayana

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Abstract

Al-Si 11.8 wt% alloy which classified to eutectic Al-Si composition usually used to produce a flat casting product with high pressure die casting process. Alloying element become an important things to determine behavior and characteristic of aluminum. Copper added into aluminum to improve strength and hardness, but there has no many studies on the effect of copper on fluidity. This fluidity study is using vacuum suction test method and the microstructure is observed with SEM/EDS. Spectrometer test has been used to find out chemical composition of sample. The result of this study shows that with copper addition from 2.25 wt% to 3.11 wt%, the fluidity value has increased 24.11% on 680oC pouring temperature. On 3.11 wt% copper composition, fluidity value has increased 14.38% from 640oC pouring temperature to 700oC pouring temperature.
THE INFLUENCE OF GRAIN REFINER ON DENDRITE ARM SPACING OF ALUMINUM ALLOY ADC 12 Suharno, Bambang; Nanda, Is Prima; Harjanto, Sri; Lirachandra, Erika
Jurnal Sains Materi Indonesia Vol 8, No 2: FEBRUARI 2007
Publisher : BATAN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (414.608 KB) | DOI: 10.17146/jsmi.2007.8.2.4776

Abstract

THE INFLUENCE OF GRAIN REFINER ON DENDRITE ARM SPACING OF ALUMINUM ALLOY ADC 12. ADC 12 is the common used materials for die casting process in producing automotive components. Grain refiner was added to aluminum ADC 12 to increase mechanical properties by decreasing grain size and improving fine distribution of gas porosity. Grain refiner also give positive effect in aluminum fluidity, where the proper addition of grain refiner will increase the fluidity. The purpose of present research is determining correlation between grain refiner addition and dendrite arm spacing, which also indirectly related to the grain size. 100% scrap of aluminum ADC12 and Al5Ti1B grain refiner were used as raw materials. Melting process has been done in a 1400 gr crucible with cokes and oxygen as the fuming energy. Argon was introduced into crucible at least in 1 minute for degassing. After degassing process accomplished, 0, 0.05, 0.1, 0.15, 0.2 % grain refiner Al5TiB, which have been choosen as experimental variable, were charged into crucible. Vacuum suction machine has been utilized to measure the aluminum fluidity at 680 0C, the common ADC 12 pouring temperature. Samples for microstructural analysis were tooken at the tip of specimen from vacuum suction test. Measurement of dendrite arm spacing (DAS) was conducted by SIGMA SCAN Pro.5 Software. The result indicated that at 680 0C, the addition up to 0.15% Al5Ti1B grain refinement reduced 50% dendrite arm spacing from 8.8 ìm (without grain refiner) to 4.5 ìm. Over 0.15% Al5Ti1B, the refinement stopped and DAS increased caused by the complex intermetallic phase (Ti-Al, Ti-B) has nucleated from the excess grain refiner.
Effect of Mechanical Tumbling Parameters on Surface Roughness and Edge Radius of Medical Grade Cobalt Chromium Alloy Nanda, Is Prima; Hassim, Mohd Hazwan; Idris, Mohd Hasbullah; Jahare, Muhammad Hafiz; Arafat, Andril
International Journal on Advanced Science, Engineering and Information Technology Vol 9, No 1 (2019)
Publisher : International Journal on Advanced Science, Engineering and Information Technology

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1359.132 KB) | DOI: 10.18517/ijaseit.9.1.4797

Abstract

Smoothly polished prosthesis surface is a crucial requirement in medical application and important feature that determine the proper response to corrosion and biocompatibility in the human body. Tumbling is one of the pre-polishing processes that can be conducted in order to improve the surface roughness of the machined prosthesis. However, the using of ceramic media for the tumbling process in medical application is not widely reported. This study was conducted to investigate the effect of mechanical tumbling parameters on the surface roughness of medical grade CoCr alloy by using alumina (Al2O3) based ceramic media. The experiment was performed with a different level of rotational speed (35, 55, and 75 rpm) and soaking time (4, 6 and 8 hours) of the tumbling process. The surface roughness of specimens before and after the process was measured using Mitutoyo Formtracer CS-5000 and the edge radius was measured using Olympus SZX9 microscope integrated with I-solution Lite software. It was figured that 6 hours tumbling time at 55 rpm showed the most significant reduction (32 %) in surface roughness (Ra) of the CoCr alloy specimen, while 8 hours tumbling time at 75 rpm showed the highest effect on the edge radius of the specimen at 63 % increment.