Next Article in Journal
NiO/Carbon Aerogel Microspheres with Plum-Pudding Structure as Anode Materials for Lithium Ion Batteries
Next Article in Special Issue
Characterization of γ′ Precipitates in Cast Ni-Based Superalloy and Their Behaviour at High-Homologous Temperatures Studied by TEM and in Situ XRD
Previous Article in Journal
The Effect of Pre-Annealing on the Evolution of the Microstructure and Mechanical Behavior of Aluminum Processed by a Novel SPD Method
Previous Article in Special Issue
Variation of Crystal Orientation and Dendrite Array Generated in the Root of SX Turbine Blades
Open AccessArticle

Fabrication and Characterization of the Newly Developed Superalloys Based on Inconel 740

Lukasiewicz Research Network-Krakow Institute of Technology, Zakopianska 73, 30-418 Cracow, Poland
Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, Mickiewicza 30, 30-059 Cracow, Poland
Consolidated Precision Products, Investment Casting Division, Hetmańska 120, 35-078 Rzeszow, Poland
Institute of Materials Research, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovakia
Faculty of Materials, Metallurgy and Recycling Technical, University of Košice, Letná 9, 042 00 Košice, Slovakia
Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovakia
Author to whom correspondence should be addressed.
Materials 2020, 13(10), 2362;
Received: 18 April 2020 / Revised: 15 May 2020 / Accepted: 15 May 2020 / Published: 21 May 2020
The chemical composition of standard Inconel 740 superalloy was modified by changes in the Al/Ti ratio (0.7, 1.5, 3.4) and addition of Ta (2.0, 3.0, 4.0%). Remelted Inconel 740 (A0) and nine variants with various chemical compositions were fabricated by lost-wax casting. The microstructure, microsegregation, phase transformation temperatures, thermal expansion coefficients and hardness of the superalloys were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, differential scanning calorimetry, dilatometry and Vickers measurements. Typical dendritic microstructure was revealed with microsegregation of the alloying elements. Segregation coefficient ki for Ti, Nb and Ta did not exceed unity, and so precipitates enriched mainly in these elements were found in interdendritic spaces. The Nb-rich blocky precipitates, MC carbides, MN nitrides, oxides, and fine γ’ was in all modified castings. Presence of other microstructural features, such as Ti-rich needles, eutectic γ-γ’ islands, small Al-rich and Cr-rich precipitates depended on the casting composition. The lowest solidus and liquidus temperatures were observed in superalloys with a high Al/Ti ratio. Consequently, in A7–A9 variants, the solidification range did not exceed 100 °C. In the A0 variant the difference between liquidus and solidus temperature was 138 °C. Hardness of all modified superalloys was at least 50% higher than for the remelted Inconel 740 (209 HV10). View Full-Text
Keywords: Inconel 740; A-USC; tantalum; superalloy; investment casting Inconel 740; A-USC; tantalum; superalloy; investment casting
Show Figures

Figure 1

MDPI and ACS Style

Grudzień-Rakoczy, M.; Rakoczy, Ł.; Cygan, R.; Kromka, F.; Pirowski, Z.; Milkovič, O. Fabrication and Characterization of the Newly Developed Superalloys Based on Inconel 740. Materials 2020, 13, 2362.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

Search more from Scilit
Back to TopTop