- 98 views
- 113 downloads
Thermal and residual stress modeling of functionally graded deposits using the PTAAM
-
- Author / Creator
- Bonias, Geoffrey
-
High maintenance costs due to significant abrasive wear of components is experienced in the energy and mining sectors despite the current use of tough and hard coatings. During the coating process significant detrimental residual stresses may build up and result in premature failure of a component. These stresses can be reduced by adopting functionally graded structures of the composite. The main goal of the present study is to design an ideal additively manufactured path and print functionally graded geometries using plasma transferred arc (PTA) with WC-Ni alloy composite. To develop a comprehensive analysis of the functionally graded deposit, the thermal history of the WC and Ni alloy powders must first be simulated as they travel through the plasma and deposit on the substrate. Predictions of particle trajectories in the plasma are compared to experimentally tracked powder particles to validate the model. The power transferred from the arc to the anode is divided into an electronic, a convective and a radiative contribution and is then estimated. The dependency of the thermal history of the WC and Ni powder particles and of the heat input from the arc to the anode on the PTA operating parameters is discussed quantitatively. Inferences from this preliminary work are then used as input data to simulate the additive manufacturing of functionally graded materials at the macro scale level. The thermal history followed by the thermal stress history of the process is predicted, and finally the residual stress distribution is obtained for a wall-shaped printed part. Simulations are performed on Abaqus for different material gradients under the same operating conditions. The residual stress profiles of each material gradient are compared to each other and to a wall without gradient. Conclusions are drawn as to the material gradation that is most susceptible to enhance the coating wear resistance from a residual stress perspective. Future work could focus on validating the thermal and residual stress model and establishing the wear characteristics of the graded deposits. Using the model, strategies could be established to optimize the temperature history of the graded coating during its printing to further reduce tensile residual stresses and reduce WC settling in the liquid bead to improve homogeneity.
-
- Graduation date
- Fall 2022
-
- Type of Item
- Thesis
-
- Degree
- Master of Science
-
- License
- This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.