การเพิ่มความแข็งของทองคำ 18 กะรัต โดยการทำให้เกิดโครงสร้างที่เป็นระเบียบ
The effect of solution treatment and aging on microstructure, ordered structure formation and hardness of 18 carat gold (75 wt % Au) were investigated. The specimens, gold-copper- silver alloy contained 5 - 20 wt % copper, were cold rolled with the thickness reduction ratio of 90 %. The experimental...
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| Format: | Theses and Dissertations |
| Language: | Thai |
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จุฬาลงกรณ์มหาวิทยาลัย
1999
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| Online Access: | https://digiverse.chula.ac.th/Info/item/dc:47267 |
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| Institution: | Chulalongkorn University |
| Language: | Thai |
| Summary: | The effect of solution treatment and aging on microstructure, ordered structure formation and hardness of 18 carat gold (75 wt % Au) were investigated. The specimens, gold-copper- silver alloy contained 5 - 20 wt % copper, were cold rolled with the thickness reduction ratio of 90 %. The experimental result indicated that the samples with 10, 15 and 20 wt.% copper were hardened by order hardening mechanism after aging treatment. The optimum aging temperature for maximum hardness was 270° c. An increase in copper content increased the as-aged hardness i.e. the maximum as-aged hardness values of the samples contained 10, 15 and 20 wt% copper were 273, 283 and 306 Vicker, an increase of 92, 123 and 129 Vicker, respectively when compared to the as-solution treated. Furthermore, the increase in copper content also increased the hardening rate, hence the time required to produce maximum hardness were reduced to 100, 60 and 30 minutes for the samples contained 10, 15 and 20 wt.% copper, respectively. In case of the sample contained 5 wt.% copper, ordered structure was not substantiated. The maximum hardness of 137 Vicker, an increase of 22 Vicker from the as-solution treated hardness, was obtained by aging treatment at 150°c for 30 minutes |
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