| 1. |
- Andersson, Joel Håkan, 1981, et al.
(författare)
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Hip-densification of alloy 718 and ati 718Plus®
- 2014
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Ingår i: 8th International Symposium on Superalloy 718 and Derivatives 2014; Pittsburgh; United States; 28 September 2014 through 1 October 2014. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. - 9781634396424 ; , s. 425-435
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Konferensbidrag (refereegranskat)abstract
- Cast Alloy 718 and ATI 718Plus® have been investigated to disclose their ability to develop Hot Isostatic Pressing (HIP) porosity which may form as a consequence of the casting process. Artificial defects were manufactured in cast Alloy 718 and ATI 718Plus® block and sealed by electron beam welding prior to the HIP treatment which was carried out at three different temperatures, namely; 1120 °C, 1165 °C, and 1190 °C at a pressure of 100 MPa. It was seen that there are no significant difference in the ability to heal pores in between cast Alloy 718 and ATI 718Plus®. No major difference in between the three different temperatures were disclosed whereas the size of the pore seem to have the biggest impact on the ability to heal, which was supported by careful SEM characterization and by simplified calculations considering two different sizes of pores.
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| 2. |
- Andersson, Joel Håkan, 1981, et al.
(författare)
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Solidification of alloy 718, ati 718Plus® and waspaloy
- 2014
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Ingår i: 8th International Symposium on Superalloy 718 and Derivatives 2014. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. - 9781634396424 ; , s. 181-192
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Konferensbidrag (refereegranskat)abstract
- Alloy 718, ATI 718Plus® and Waspaloy have been investigated in terms of what their respective solidification process reveals. Differential thermal analysis was used to approach the task together with secondary electron and back scattered electron detectors equipped with an energy dispersive X-ray spectroscopy detector. These experimental methods were used to construct pseudo binary phase diagrams that could aid in explaining solidification as well as liquation mechanisms in processes such as welding and casting. Furthermore, it was seen that Waspaloy has the smallest solidification range, followed by Alloy 718, and finally ATI 718Plus® possessing the largest solidification interval in comparison.
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| 3. |
- Andersson, Joel Håkan, 1981
(författare)
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Weldability of Ni-based superalloys
- 2014
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Ingår i: 8th International Symposium on Superalloy 718 and Derivatives 2014; Pittsburgh; United States; 28 September 2014 through 1 October 2014. - : John Wiley & Sons, Inc.. - 9781634396424 ; , s. 249-262
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Konferensbidrag (refereegranskat)abstract
- This paper reviews the inherent weldability of precipitation hardening Ni-based superalloys commonly used in structural components of aircraft engines. Weldability often refers to alloys resistant to cracking during welding which for superalloys is difficult to comprehend since specific liquation and cracking mechanism may differ in this class of materials. A new procedure of evaluating the weldability as well as susceptibility towards strain age cracking of these alloys is proposed in which standard metallographic examinations are used to understand the cracking mechanisms in parallel with systematic ductility measurements such as Varestraint or Gleeble testing.
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| 4. |
- Cedergren, Stefan, 1982, et al.
(författare)
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Influence of deformed surface layer when machining wrought alloy 718 in an annealed and in a pre-strained condition
- 2014
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Ingår i: 8th International Symposium on Superalloy 718 and Derivatives 2014; Pittsburgh; United States; 28 September 2014 through 1 October 2014. - Hoboken, NJ, USA : John Wiley & Sons, Inc.. - 9781634396424 ; , s. 263-271
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Konferensbidrag (refereegranskat)abstract
- Superalloys are difficult to cut, mainly due to their preserved strength at elevated temperatures and their exceptional work hardening, where the latter results in a deformed layer on the machined surface. The thickness and degree of deformation of this layer depends on several parameters, such as cutting speed, uncut chip thickness, tool material and edge geometry. This layer enters the cutting zone of subsequent revolutions in turning or in milling. Under certain circumstances, as when the uncut chip thickness is small, all deformation at subsequent machining takes place within the deformed layer. The same phenomenon may occur at the outer edge of the cutting zone where the unrestricted material flow leads to burr formation. The deformed layer at the outer edge is suggested as the cause for notch wear often found when machining Superalloys. In this paper the effect of deformed layer on machining is examined through controlled experiments on the material in to different states of strain; in the annealed state without any remaining strain and with a substantial amount introduced by tensile straining. The results showed that cutting forces were reduced when pre-straining the material. Tool wear was similar in both materials, with large scatter due to built-up edge formation.
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