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Cooling Rate Study of Nickel-Rich Material During Thermal Treatment and QuenchTo investigate quench cracking that results from water quenching after heat treatment of binary and Ni-rich material, cooling rates of specimens were measured during quenching and hardness post-thermal treatment. For specific applications binary Ni-Ti is customarily thermally treated and quenched to attain desired mechanical properties and hardness. However, one problem emerging from this method is thermal cracking, either during the heat treatment process or during the specimen's application. This can result in material and equipment failure as well as financial losses. The objective of the study is to investigate the internal cooling rate of 60-NiTi during quenching and determine possible factors causing thermal cracking. Cubic (1 in.3) samples of both material were heat treated in air at 1000 deg C for 2 hrs and quenched in room temperature water using two methods: (1) dropped in the water and (2) agitated in the water. Hardness of the two fore-mentioned methods was measured post heat treatment. Results indicate that the quenching method had an effect on cooling rate during quenching but hardness was observed to be essentially the same through the thickness of the samples.
Document ID
20160013862
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Thomas, Fransua
(NASA Glenn Research Center Cleveland, OH United States)
Murguia, Silvia Briseno
(University of North Texas Denton, TX, United States)
Date Acquired
November 30, 2016
Publication Date
November 1, 2016
Subject Category
Aeronautics (General)
Space Sciences (General)
Metals And Metallic Materials
Report/Patent Number
GRC-E-DAA-TN33856
E-19293
NASA/TM-2016-219387
Funding Number(s)
WBS: WBS 477547.01.01.22
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Thermal Crack
Thermal Treatment
Nitinol
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