The Influence of Shell Mold Composition on the As-cast Macro- and Micro-structure of Thin-Walled IN713C Superalloy Castings

Abstract

In the investment casting process, the building of ceramic layers around the wax pattern is the main timeconsuming stage. Increasing their number ensures sufficient mechanical properties, but also lengthens the whole process, including drying time and preheating of the mold. Four molds for casting Ni-based superalloy IN713C were strengthened by glass fibers, included in the slurry, and metal powder, of Al, Cu, Fe or Ni, in the coverage. Castings were subjected to microstructural investigations in order to find out if the new design can be promising for the manufacture of jet engine components. Bend tests revealed that the green strengths of all new molds were higher, at least 3.65 MPa, than that of the unmodified molds, 3.0 MPa. Optical microscopy revealed that the composition of a mold had a strong influence on stereological parameters of equiaxed IN713C grains. Microstructural observation and hardness measurements of castings revealed differences in the volume fraction of strengthening phases, porosity and hardness. The microstructure due to the complex chemical composition of IN713C consisted of several phases including ternary eutectics as a consequence of L fi c + Ni 7 Zr 2 + (Nb, Zr)C. Keywords aviation, glass fibers, investment casting, metal powder, shell mold This article is an invited submission to JMEP selected from presentations at the 73rd World Foundry Congress and has been expanded from the original presentation. 73WFC was held in Krakow, Poland, September 23-27, 2018, and was organized by the World Foundry Organization and Polish FoundrymenÕs Association.

Analysis of γ′ Precipitates, Carbides and Nano-Borides in Heat-Treated Ni-Based Superalloy Using SEM, STEM-EDX, and HRSTEM

“…This impact was the result of borides’ formation in the grain boundaries. A similar effect was obtained in many other superalloys, thanks to which boron is still an essential alloying element [ 30 , 31 , 32 ]. In the following years, the design of polycrystalline alloys assumed the use of all previously known mechanisms.…”

The Effect of CoAl2O4 as a Nucleating Agent and Pouring Temperature on the Microstructure and Properties of Inconel 713C® Nickel-Based Superalloy Castings

“…Cast aerospace engine components produced by conventional lost-wax casting often have a coarse and inhomogeneous grain structure. However, these features can be controlled by adjusting the melt-pouring temperature and the composition of the prime coating in the shell mold [ 12 ]. Increasing the pouring temperature can enhance the filling ability of thin-walled blades and vanes but can also lead to grain coarsening due to decreased cooling rates [ 13 ].…”

Selected Properties of High Entropy Alloys Based on the AlFeMnNbNiTi System

“…One example includes materials based on the Co 1.5 CrFeNi 1.5 Ti 0.5 (Yeh et al 2014) system, which exhibits excellent high temperature properties and is considered as a competitive materials for nickel based alloys. Preparing elements made of refractory high entropy alloys using special foundering methods, such as casting into multilayer molds with ceramic shells, has an influence on the material behavior under high temperatures, broadening this application (Rakoczy et al 2019;Grudzień-Rakoczy et al 2020). Another example is high entropy steels based on the Fe-Mn-Al-Si-C system having excellent mechanical properties in low temperatures (below 0 • C) (Raabe et al 2015).…”