Selective laser melting of Co-29Cr-6Mo alloy with laser power 180–360 W: Cellular growth, intercellular spacing and the related thermal condition
- Department of Mechanical Engineering, Auckland University of Technology (New Zealand)
Highlights: • Increasing laser power increases the track size but not the track shape significantly. • Solidification mode and texture are similar over the range of laser power used. • Intercellular spacing is not affected by laser power but decreases slightly with growth angle. • Thermal gradient and cooling rate have been estimated to be ~ 2 × 10{sup 7} K/m and ~ 2 × 10{sup 6} K/s, respectively. - Abstract: A feature of solidification during selective laser melting (SLM) is cellular growth. Thus, how growth direction and cell size may be affected and possibly be controlled by SLM parameters are important to be understood. Furthermore, intercellular spacing (λ{sub 1}) is suggestive of the thermal condition during solidification which needs to be known for advancing the understanding of SLM. In this work, grain solidification orientation and λ{sub 1} of a Co-Cr-Mo alloy produced by SLM over a range of laser power (P = 180–360 W) with other parameters kept unchanged have been evaluated. It has been found that the overall preferred growth of cellular solidification is not significantly affected by P. This is because, over the range of P values used, the shape of track did not change sufficiently to result in a significant variation of growth direction during epitaxial growth. It has also been found that P does not affect λ{sub 1}. This suggests, since growth rate (R) relates to scan speed (v) which is unchanged, P does not significantly affect the temperature gradient of the solidification front (G). From the measured λ{sub 1} and estimated R, G and thus cooling rate ( T-dot ) can be estimated following the commonly used primary arm spacing model. The estimated G and T-dot which could not be directly measured will be compared with those predicted by simulation and the estimated T-dot will also be compared with those determined by using an emperical relationship from literature.
- OSTI ID:
- 22805738
- Journal Information:
- Materials Characterization, Vol. 135; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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