Order hardening of platinum alloys

 

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dc.contributor.advisor Miller, Duncan en_ZA
dc.contributor.advisor Lang, Candy en_ZA
dc.contributor.author Towle, Nicholas Richard en_ZA
dc.date.accessioned 2016-11-07T17:40:57Z
dc.date.available 2016-11-07T17:40:57Z
dc.date.issued 1999 en_ZA
dc.identifier.citation Towle, N. 1999. Order hardening of platinum alloys. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/22429
dc.description.abstract The hardening behaviour of three cold-worked platinum alloys, Pt 5 at% Mo, Pt 5 wt% Ru and Pt 5 wt% Cu, has been investigated through a systematic series of heat treatments. All three of the experimental alloys showed a hardness increase during annealing within a specific temperature range. The hardness of the Pt-Mo and Pt-Ru alloys was found to increase rapidly at annealing temperatures above the recrystallisation temperature, with the final hardness similar to the original coldworked hardness. The hardness of Pt-Cu showed an increase of up to 30% at low annealing temperatures of between 200°C and 500°C. In addition, the Pt-Cu alloy also showed the increased hardness found in Pt-Mo and Pt-Ru at high annealing temperatures, but the hardness increase was not to the same extent. Specimens subjected to the annealing treatments were studied by means of optical, scanning electron and transmission electron microscopy, in order to determine the effect of annealing on microstructure and structural order. Resistivity, XRD and OTA techniques were employed in order to study the mechanisms of ordering with temperature, but these techniques did not produce any significant results. It was concluded that the most likely cause for the hardness increase observed in all three experimental alloys was due to a change in structural order upon annealing. The Pt-Mo and Pt-Ru alloys hardened through an increase in short-range order at annealing temperatures above the recrystallisation temperature. The Pt-Cu alloy hardened through the development of long-range order on annealing between 200°C and 500°C. This increase in hardness was in· addition to the high dislocation density in the alloy specimen due to prior cold-work. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Materials Engineering en_ZA
dc.title Order hardening of platinum alloys en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering and the Built Environment
dc.publisher.department Centre for Materials Engineering en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Towle, N. R. (1999). <i>Order hardening of platinum alloys</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering. Retrieved from http://hdl.handle.net/11427/22429 en_ZA
dc.identifier.chicagocitation Towle, Nicholas Richard. <i>"Order hardening of platinum alloys."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1999. http://hdl.handle.net/11427/22429 en_ZA
dc.identifier.vancouvercitation Towle NR. Order hardening of platinum alloys. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1999 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/22429 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Towle, Nicholas Richard AB - The hardening behaviour of three cold-worked platinum alloys, Pt 5 at% Mo, Pt 5 wt% Ru and Pt 5 wt% Cu, has been investigated through a systematic series of heat treatments. All three of the experimental alloys showed a hardness increase during annealing within a specific temperature range. The hardness of the Pt-Mo and Pt-Ru alloys was found to increase rapidly at annealing temperatures above the recrystallisation temperature, with the final hardness similar to the original coldworked hardness. The hardness of Pt-Cu showed an increase of up to 30% at low annealing temperatures of between 200°C and 500°C. In addition, the Pt-Cu alloy also showed the increased hardness found in Pt-Mo and Pt-Ru at high annealing temperatures, but the hardness increase was not to the same extent. Specimens subjected to the annealing treatments were studied by means of optical, scanning electron and transmission electron microscopy, in order to determine the effect of annealing on microstructure and structural order. Resistivity, XRD and OTA techniques were employed in order to study the mechanisms of ordering with temperature, but these techniques did not produce any significant results. It was concluded that the most likely cause for the hardness increase observed in all three experimental alloys was due to a change in structural order upon annealing. The Pt-Mo and Pt-Ru alloys hardened through an increase in short-range order at annealing temperatures above the recrystallisation temperature. The Pt-Cu alloy hardened through the development of long-range order on annealing between 200°C and 500°C. This increase in hardness was in· addition to the high dislocation density in the alloy specimen due to prior cold-work. DA - 1999 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1999 T1 - Order hardening of platinum alloys TI - Order hardening of platinum alloys UR - http://hdl.handle.net/11427/22429 ER - en_ZA


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