U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Nik Hrabe (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 45

Investigation of melt pool dynamics and solidification microstructures of laser melted Ti-6Al-4V powder using X-ray synchrotron imaging

April 10, 2024
Author(s)
Nicholas Derimow, Madelyn Madrigal-Camacho, Orion Kafka, Jake Benzing, Edward Garboczi, Samuel J. Clark, Suveen Mathaudhu, Nik Hrabe
Titanium alloy (Ti-6Al-4V) is widely used in additive manufacturing (AM) industry. However, as laser powder-bed fusion (PBF-L) additive manufacturing (AM) advances towards reliable production of titanium parts, a thorough understanding of the process

Evidence for contributions of lack-of-fusion defects and dislocations to acoustic nonlinearity and loss in additively manufactured aluminum

February 2, 2024
Author(s)
Ward L. Johnson, Paul R. Heyliger, Jake Benzing, Orion Kafka, Newell Moser, Derek Harris, Jeremy Iten, Nik Hrabe
Resonant acoustic nonlinearity and loss have previously been found to be correlated with porosity in additively manufactured (AM) commercially pure aluminum and stainless steel, and this effect offers a potential basis for rapid nondestructive

AM Bench 2022 Macroscale Tensile Challenge at Different Orientations (CHAL-AMB2022-04-MaTTO) and Summary of Predictions

January 16, 2024
Author(s)
Newell Moser, Jake Benzing, Orion Kafka, Jordan Weaver, Nicholas Derimow, Ross Rentz, Nik Hrabe
The additive manufacturing benchmarking challenge described in this work was aimed at the prediction of average stress–strain properties for tensile specimens that were excised from blocks of non-heat-treated IN625 manufactured by laser powder bed fusion

Enhanced strength of additively manufactured Inconel 718 by means of a simplified heat treatment strategy

October 27, 2023
Author(s)
Jake Benzing, Nicholas Derimow, Orion Kafka, Nik Hrabe, Philipp Schumacher, Don Godfrey, Chad Beamer, Priya Pathare, Jay Carroll, Ping Lu, Isaiah Trujillo, Frank DelRio
This study simplified the heat treatment route and reduced the post-processing burden for laser powder bed fusion IN718 (a nickel-based superalloy). The tailored route retained advantageous microstructures and improved tensile strength when compared to the

Effects of as-built surface with varying number of contour passes on high-cycle fatigue behavior of additively manufactured nickel alloy 718

August 5, 2023
Author(s)
Orion Kafka, Jake Benzing, Nicholas Derimow, Philipp Schumacher, Lucas Koepke, Chad Beamer, Donald Godfrey, Nik Hrabe
High cycle fatigue life of laser-powder bed fusion (L-PBF) parts depends on several factors; as-built surfaces, when present, are a particular concern. This work measures as-built L-PBF surfaces with X-ray computed tomography, and uses rotating beam

Effects of local processing parameters on microstructure, texture, and mechanical properties of electron beam powder bed fusion manufactured Ti-6Al-4V

August 27, 2022
Author(s)
Edwin Schwalbach, Jake Benzing, Vikas Sinha, Todd Butler, Adam Pilchak, Kevin Chaput, Norman Schehl, Reji John, Nik Hrabe
Electron beam powder bed fusion scan strategies for parts or part groupings of various sizes and scan line lengths have been found to inadvertently lead to significant variations in crystallographic texture and mechanical properties for Ti–6Al–4V. This

Assessment of intra-build variations in tensile strength in electron beam powder-bed fusion Ti-6Al-4V part 1: Effects of build height

June 2, 2022
Author(s)
Nicholas Derimow, Alejandro Romero, Aldo Rubio, Cesar Terrazas, Newell Moser, Orion Kafka, Jake Benzing, Francisco Medina, Ryan Wicker, Nik Hrabe
In this work, rectangular blocks of electron beam powder-bed fusion (PBF-EB) additively manufactured (AM) Ti-6Al-4V were built, such that a total of 68 mini-tensile test coupons could be extracted for mechanical testing over a range of build height and

Assessment of intra-build variations in tensile strength in electron beam powder-bed fusion Ti-6Al-4V part 2: Effects of powder mixing

May 31, 2022
Author(s)
Nicholas Derimow, Jake Benzing, Orion Kafka, Newell Moser, Priya Pathare, Michael Walker, Frank DelRio, Nik Hrabe
In Part 2 of this paper series, high-throughput tensile testing and characterization of porosity, microstructure, and oxygen content was carried out on Ti-6Al-4V samples that were fabricated via electron beam powder-bed fusion (PBF-EB) to test our

In situ absorption synchrotron measurements, predictive modeling, microstructural analysis, and scanning probe measurements of laser melted Ti-6Al-4V single tracks for additive manufacturing applications

December 29, 2021
Author(s)
Nicholas Derimow, Edwin Schwalbach, Jake Benzing, Jason Killgore, Aly Artusio-Glimpse, Nik Hrabe, Brian Simonds
In this work, the fundamental processing-structure-property (PSP) relationships that govern laser-based additive manufacturing were investigated with the Ti-6Al-4V alloy. X-ray synchrotron imaging carried out in conjunction with in-situ integrating sphere

Sintered powder oxidation variation as a function of build height for titanium alloy produced by electron beam powder-bed fusion

November 26, 2021
Author(s)
Nicholas Derimow, Alejandro Romero, Aldo Rubio, Cesar Terrazas, Francisco Medina, Ryan Wicker, Nik Hrabe
It is well-established that titanium alloy (Ti-6Al-4V) powder oxidizes during electron beam powder-bed fusion (PBF-EB) due to the high background temperatures resulting from layer preheating and sintering of the powder bed before melting. However, it is

Evaluation of a Modified Void Descriptor Function to Uniquely Characterize Pore Networks and Predict Fracture Location in Additively Manufactured Metals

November 15, 2021
Author(s)
Dillon Watring, Jake Benzing, Orion Kafka, Li-Anne Liew, Newell Moser, John Erickson, Nik Hrabe, Ashley Spear
Variations in additive manufacturing (AM) processing parameters can lead to variations in porosity, making it challenging to predict pore- or void-sensitive mechanical response in AM metals. A recently developed pore metric, the void descriptor function

Damage tolerant design of additively manufactured metallic components subjected to cyclic loading: State of the art and challenges

March 18, 2021
Author(s)
Uwe Zerbst, Giovanni Bruno, Jean-Yves Buffiere, Thomas Wegener, Tao Wu, Xiang Zhang, Nikolai Kashaev, Giovanni Meneghetti, Nik Hrabe, Mauro Madia, Tiago Werner, Kai Hildgenburg, Radek Proch?zka, Martina Koukol?kov?, Jan D?ugan, Benjamin M?ller, Stefano Beretta, Alexander Evans
Undoubtedly, a better understanding and the further development of approaches for damage tolerant component design of AM parts are among the most significant challenges currently facing the use of these new technologies. This article presents a thorough