Effect of heat treatment on cold sprayed Ti-6Al-4V alloy
In this dissertation, cold sprayed Ti-6Al-4V coatings were annealed at six different conditions to investigate the heat treatment effect. With the temperature increasing from 300 to 950 °C, the atomic diffusion between the particles continuously eliminated the pores in the coatings. And ultraf...
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| Main Author: | |
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| Other Authors: | |
| Format: | Theses and Dissertations |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | http://hdl.handle.net/10356/75707 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | In this dissertation, cold sprayed Ti-6Al-4V coatings were annealed at six different
conditions to investigate the heat treatment effect. With the temperature increasing
from 300 to 950 °C, the atomic diffusion between the particles continuously
eliminated the pores in the coatings. And ultrafine grain could be found in the
microstructure of coating heated at 950 oc. While both top surface and cross section
of the coating could obtain the highest and lowest hardness at 400 oc and 9 50 °C,
respectively.
By simulating the particle deposition process in the ABAQUS finite element
software, the stress and temperature profiles were evaluated. The single impact
results showed that higher impact velocity led to higher stress and temperature,
especially at the interface. Before the particle finally deposited on the substrate, the
stress reduced by nearly 10% due to localized heat. And the second impact revealed
that the interface of coating layer and substrate experienced much higher stress than
other area, which could lead to cracks of the coating.
In conclusion, heat treatment has significant influence on the microstructure and
mechanical properties of cold sprayed Ti-6Al-4V coatings, and might has certain
effect on the residual stress based on the simulation results. |
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