Semester

Summer

Date of Graduation

2023

Document Type

Problem/Project Report

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Bruce Kang

Committee Member

Kostas Sierros

Committee Member

Zhichao Liu

Abstract

Alloy Inconel 718 is a Ni based superalloy used for high temperature applications including turbine blades, turbocharger rotors and nuclear reactors. Inconel 718 is a popular commercial atomized powder that has limitations in performance for use in additive manufacturing applications due to poor part quality and efficiency of current fabrication methods. Developing new compositions and additive manufacturing (AM) methodologies of IN718 is critical to improve the quality and the efficiency of IN718 parts manufacturing. Developing new additive manufacturing methodology that produces higher quality parts made of IN718 as compared to current methods has the potential to greatly impact industry, academia, manufacturing speed and manufacturing labor. The type of additive manufacturing machinery that is utilized in this research is binder jet three-dimensional printing (BJ3DP). This document overviews BJ3DP and the methodology and science behind how BJ3DP printers manufacture parts. The research performed and presented in this document attempts to better understand what heating conditions of IN718 parts manufactured by BJ3DP produces high quality parts. The goal of this research is to improve the existing issues of using IN718 for AM through providing heating suggestions based on experimental results from tested heating profiles that improve the quality of IN718 parts manufactured by BJ3DP. The research performed utilized IN718 from the company Carpenter Additive and two different particle size distributions of IN718 were examined for BJ3DP manufacturing. IN718F (fine particle distribution) and IN718E (course particle size distribution) powders were used to produce parts using a BJ3DP located at the University of Pittsburgh. Heating profiles were performed on the IN718F and IN718E parts that were produced using a BJ3DP and the results and conclusions on the heating profile performance are presented. Hardness testing was performed on the IN718F and IN718E BJ3DP parts after heating and the results are presented. The research also examined a theoretical approach to produce quality parts through taking IN718F powder mixed with binder and compressing the powder binder mixture into pellets which were then exposed to various heating profiles. This study utilized a stainless steel 0.5-inch inner diameter pressing die to create IN718F mixed with binder pellets pressed at 10.5 tons and held at that force for 10 minutes. The compressed pellets where heated using a horizontal tube furnace (HTF) at different heating profiles and the results of the compressed pellets manufacturing method was compared and contrasted against the results of the heating profiles performed on the BJ3DP IN718F and IN718E manufactured parts. Hardness measurements were performed on IN718F compressed heat treated pellets that were exposed to different heating profiles. SEM images are provided of the as-received composition of IN718F. The liquid binder that was utilized in this research is called AquaFuse binder and is produced by the company ExOne. Experimentation was performed to determine a minimum range of binder needing to be mixed with IN718F to produce compressed green pellets that can survive being removed from the pressing die and transported to the HTF for high temperature heat treatment. The results of the minimum range of binder needing to be mixed with IN718F to produce compressed pellets are presented. Testing of heating profiles was performed in an attempt to produce quality sintered simple and complex geometry BJ3DP parts that were made using IN718F and IN718E powders mixed with AquaFuse binder additive, 3D printed in a BJ3DP printer and heated in an argon environment to increase the density and strength of the specimens with minimal deformation and volumetric shrinkage. Testing was performed to map the heating profile that will produce quality sintered IN718F compressed pellets that contain a quantity of AquaFuse binder.

Download

Share

COinS