PEMBEKUAN SEARAH PADUAN Al - (1�12)%Si
| Main Authors: | , MUHAMAD, , Dr. Suyitno, ST., M.Sc. |
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| Format: | Thesis NonPeerReviewed |
| Terbitan: |
[Yogyakarta] : Universitas Gadjah Mada
, 2013
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| Subjects: | |
| Online Access: |
https://repository.ugm.ac.id/120708/ http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=60746 |
Daftar Isi:
- Microstructure modification is one way to improve the material properties. Materials with columnar microstructure have good resistance to creep and greater creep strain. Columnar microstructure can be formed by unidirectional solidification, where the grain growth process is directed in line with the rate of heat flow. The purpose of this research is to study the influence of Si concentration and cooling rate on the formation of columnar microstructure on material of aluminumsilicon (1-12% Si) alloy with unidirectional solidification of vertical natural convection. Experiment was initiated by designing and manufacturing of electric furnaces for melting and unidirectional solidification. Al-Si alloy samples with concentrations of 1.6, 2.8, 3.9, 5.6, 7.4 and 10.8 wt% Si were melted in an electric furnace and then inserted in the mold of a thin stainless steel tube (ID 11/16â��, OD 3/8â�� and length of 80 mm). Subsequently the samples were solidified under the conditions of steady on electric furnace equipped with unidirectional solidification system vertically through the water-cooled metal chiller mounted on the bottom of the mold, with a constant growth rate (6.38-40 Î1⁄4m/sec) on the temperature gradient between 1.47-7.78°C/mm. Thermocouples K- Type were mounted at three of difference place from the surface of the mold and the chiller to measure the temperature during directional solidification. Solidification parameters (Si concentration and cooling rate) have been observed as a function of the structure formation. The experimental results reveal that the growth of columnar dendrite structure with the primary dendrite arm spacing is smooth and uniformly present in alloys with concentrations of 5.6 and 7.4% Si. At higher concentrations, columnar dendrites grow with the primary dendrite arm spacing is more coarse, while the lower Si concentrations tend to form equiaxed grain structure. At low cooling rate (0.05°C/sec), the growth of secondary dendrite arm increased and primary dendrite growth decreased. In contrast to the higher cooling rate (0.16°C/sec), growth of primary dendrites increased and secondary dendrite growth reduced.