| 1. |
- Lundbäck, Andreas, et al.
(författare)
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Modeling and Experimental Measurement with Synchrotron Radiation of Residual Stresses in Laser Metal Deposited Ti-6Al-4V
- 2016
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Ingår i: Proceedings of the 13th World Conference on Titanium. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. - 9781119293668 - 9781119296126 ; , s. 1279-1282
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Konferensbidrag (refereegranskat)abstract
- There are many challenges in producing aerospace components by additive manufacturing (AM). One of them is to keep the residual stresses and deformations to a minimum. Another one is to achieve the desired material properties in the final component. A computer model can be of great assistance when trying to reduce the negative effects of the manufacturing process. In this work a finite element model is used to predict the thermo-mechanical response during the AM-process. This work features a physically based plasticity model coupled with a microstructure evolution model for the titanium alloy Ti -6Al-4V. Residual stresses in AM components were measured non-destructively using high-energy synchrotron X-ray diffraction on beam line ID15A at the ESRF, Grenoble. The results are compared with FE model predictions of residual stresses. During the process, temperatures and deformations was continuously measured. The measured and computed thermal history agrees well. The result with respect to the deformations agrees well qualitatively. Meaning that the change in deformation in each sequence is well predicted but there is a systematic error that is summing so that the quantitative agreement is lost.
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| 2. |
- Tolvanen, Sakari, 1984, et al.
(författare)
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Fatigue strength dependence on microstructure and defects in Ti-6Al-4V welds
- 2016
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Ingår i: Proceedings of the 13th World Conference on Titanium. - 9781119293668 ; , s. 311-315
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Konferensbidrag (refereegranskat)abstract
- The effect of defects and microstructure on mechanical properties of Ti-6Al-4V welds produced by plasma arc welding (PAW) and tungsten inert gas welding (TIG) was studied. Both types of welds were fatigue tested at 250°C. Weld microstructure, fracture surfaces, crack initiation sites and internal defects such as porosity were studied using optical microscopy and SEM. Also microhardness measurements were performed. The fatigue performance of the welds tested at 250°C was found to be comparable to each other. Fatigue cracks in almost all samples were found to initiate at pores, especially the ones close to the sample surface. Large pores and pores close to the surface were found to have the largest effect on fatigue life. The weld microstructures consisted of coarse prior β-grains.
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