STUDY OF EFFECT OF NIOBIUM ADDITION ON TITANIUM ALLOYS (Ti-25Mo) AND SOLUTION HEAT TREATMENT TEMPERATUR ON TITANIUM β-PHASE AND CORROSION RESISTANCE
The prevalence of injury trends increased from 7.5% (RKD 2007) to 8.2% (RKD 2013). Based on this fact it is necessary to developed research on implants for fractures. For bone implants (orthopaedic), a metal must have excellent toughness, elasticity, hardness, strenght and good corrosion resistance...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/21851 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | The prevalence of injury trends increased from 7.5% (RKD 2007) to 8.2% (RKD 2013). Based on this fact it is necessary to developed research on implants for fractures. For bone implants (orthopaedic), a metal must have excellent toughness, elasticity, hardness, strenght and good corrosion resistance and fatigue resistance. Titanium alloy becomes one of the most attractive implant materials because of its lightness, highly resistant to corrosion in the body, biocompatible, and also has a low elastic modulus. Molybdenum (Mo) is a β-phase stabilizer in titanium alloys and Niobium (Nb) is a non-toxic and non-allergic element and can also function as a β-phase stabilizer. Addition of Mo and Nb is expected to decrease modulus of elsaticity and increase the alloy strength. In fact, it is known that the stabilizers Mo and Nb can form homogenous solid solution with Ti in all titanium alloys with a certain concentration. Therefore, this study aims to study the effect of niobium addition and solution heat treatment temperatur to β phase and corrosion resistance. <br />
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The study begins with the preparation of titanium sponge, molybdenum rod, niobium wire in accordance with the composition on a 20 gram basis. The metal is then mixed in the mold to be melted using a DC Mini Arc Furnace tool. After homogenization at 1000 °C for 12 hours,the alloy is cutted and undergoes the solution heat treatment stage at 650°C and 750°C for 1 hour, followed by air cooling. Microscopic observation is performed using optical microscope and scanning electron microscope (SEM) .Elemental content on each phase is examined by electron dispersive spectroscopy (EDS), hardness of the alloy is analyzed by vicker hardness tester and the corrosion resistance is analyzed by tafel extarapolation using potensiostat. <br />
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The experimental results show the microstructure of the Ti-25Mo-15Nb as cast alloy formed a martensitic structure in the form of lamellar needle,whereas after the solution heat treatment the microstructure, transforms into parallel plates. The β phases are formed on all the alloys that solution heat treated at temperatur of 750°C, and a small number of α phases are also formed. Ti25Mo-15Nb alloy with solution treatment at750oC shows the best corrosion resistance with corrosion rate of 0.0013825 mmpy. |
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