Additive Manufacturing of Refractory Metallic Materials: Additive Manufacturing of Refractory Alloys and High Entropy Alloys
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Additive Manufacturing Committee, TMS: Refractory Metals & Materials Committee
Program Organizers: Antonio Ramirez, Ohio State University; Jeffrey Sowards, NASA Marshall Space Flight Center; Isabella Van Rooyen, Pacific Northwest National Laboratory; Omar Mireles, Los Alamos National Laboratory; Eric Lass, University of Tennessee-Knoxville; Faramarz Zarandi, RTX Corporation; Edward Herderick, NSL Analytical; Matthew Osborne, Global Advanced Metals
Tuesday 8:00 AM
March 1, 2022
Room: 262C
Location: Anaheim Convention Center
Session Chair: Eric Lass, University of Tennessee - Knoxville ; Matt Osbourne , Global Advanced Metals; Jeffrey Sowards , Nasa - MSFC
8:00 AM
Additive Manufacturing of Refractory High Entropy Alloys: Shahryar Mooraj1; Xuesing Fan2; George Kim3; Wen Chen1; Peter Liaw2; Wei Chen3; 1UMass Amherst; 2University of Tennessee, Knoxville; 3Illinois Institute of Technology
Refractory high entropy alloys (RHEA) are known to be extremely difficult to process due to the high melting points of the constituent elements. Many RHEA systems can also include elements with vastly different melting points like Ti and Ta which can lead to large freezing range with significant chemical segregation. In this talk I will outline a laser additive manufacturing method to process TiTaZrNb alloy which shows superior mechanical properties to the as-cast counterpart. The printed alloy also shows more homogeneous elemental distribution, reducing the need for post-processing treatments like homogenization. I will also detail how we used synchrotron x-ray diffraction to explore the different mechanical behaviors of the 3D-printed and as-cast alloys, and the microstructural origin of such mechanical behavior difference.
8:20 AM
Effect of Minor Titanium and Aluminum Addition on Ductility of Refractory High Entropy Alloy: Surya Bijjala1; Pankaj Kumar1; 1University of New Mexico
Refractory metal and alloys have been considered viable structural materials for high-performance engines operating at a very high temperature. The limited manufacturing due to poor ductility and fracture toughness of these materials is the major barrier to use. These characteristics of refractory metal and alloys are primarily due to interstitial impurity at grain boundaries. Alloy re-designing can improve the ductility and fracture toughness of refractory metal and alloys by reducing the GB sensitivity for interstitial elements. The present research is focused on single-phase refractory high entropy alloy (RHEA) MoVNbTaW-X, where X [= titanium (Ti), and aluminum (Al)]. The effect of Ti and Al addition on the ductility and strength both at room temperature and high temperature is rationalized in additively manufactured by powder metallurgy, MoVNbTaW RHEA.
8:40 AM
Mechanical Properties and Microstructural Characteristics of Additively Manufactured C103 Niobium Alloy: Prithvi Awasthi1; Priyanka Agrawal1; Ravi Haridas1; Rajiv Mishra1; Michael Stawovy2; Scott Ohm2; Aidin Imandoust1; 1University of North Texas; 2H.C. Starck Solutions
This research work aims to investigate the fitness of Nb-based C-103 alloy for laser based additive manufacturing (AM) technologies as a benchmark for the development of AM friendly Nb-based alloys. Crack free C-103 specimens with relative densities of above 99% were fabricated using laser powder bed fusion technology. Tensile and compression test results showed superior mechanical properties as compared to wrought C-103 counterparts. Improved mechanical performance was attributed to the high density of dislocations and formation of dislocation cell-structures revealed by transmission electron microscopy techniques. Electron backscattered diffraction analysis revealed columnar grain structure with <001>||BD fiber texture, which was consistent with the observed anisotropy in the machinal behavior. Fractography observations revealed a mix of ductile and brittle fracture behavior, wherein cleavage-like features originated from lack of fusion defects.
9:00 AM
Laser Beam Directed Energy Deposition Process Optimization for Refractory High Entropy Alloys: Erin Barrick1; Raymond Puckett1; Shaun Whetten1; Jonathan Pegues1; Michael Melia1; Remi Dingreville1; Sal Rodriguez1; Andrew Kustas1; 1Sandia National Laboratories
Refractory high entropy alloys (RHEAs) are emerging materials that have attracted attention for exceptional properties, such as high melting temperatures, retention of high-strength at elevated temperature, and resistance to degradation in harsh environments. Recently, additive manufacturing (AM) has been used to rapidly screen novel RHEA compositions for fabricability, microstructure, and properties. Comparatively less attention has been devoted to optimizing printing process parameters to produce defect-free parts. In this study, laser beam directed energy deposition was used to fabricate compact metallurgical specimens using various processing parameters (e.g., laser power, scan velocity) for alloys containing Mo, Nb, Ta, Ti, V, and W constituents. Microstructural characterization was accomplished using scanning electron microscopy, including electron backscattered diffraction, to understand the effects of processing variables on defect formation. The resulting printing strategies can be adapted to other alloys containing high melting temperature constituents. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525
9:20 AM Break
9:40 AM
Design and Development of 3D Printable Nb-based Alloys for High Temperature Applications: Ishtiaq Ahmed Fazle Rabbi1; Prithvi Awasthi1; Aidin Imandoust1; 1University of North Texas
Additive manufacturing (AM) offers ample opportunities to broaden the application of refractory metals and alloys by alleviating manufacturing challenges, such as high-temperature thermomechanical processing and machining. Nb, with a bulk density of 8.4 g/cc and good room temperature ductility, is a viable base material for the development of new AM alloys with superior high temperature performance and acceptable additive manufacturing attributes. This work aims to examine the compatibility of Nb-xW-xTi-1HfC wt.% alloys with laser-based additive manufacturing technologies. Chemical compositions of interest were selected based on the CALPHAD simulations, followed by powder prototyping and process parameter development. The microstructure and mechanical properties of AM fabricated specimens were characterized to determine the present phases, to analyze grain size and orientation, and to compare the mechanical performance of the experimental compositions. The acquired data was also used to validate the simulation results, finalize the chemical composition(s), and further improve the process parameters.