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Ben Williams

Publications and source records attributed to Ben Williams.

9 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Welding of Crack Sensitive Aluminum Alloys for Liquid Rocket Propulsion Applications

In this welding test campaign, electron beam welding (EBW) and manual gas tungsten arc welding (GTAW) processes were utilized to join an additively manufactured aluminum alloy nozzle to a wrought aluminum flange. Both aluminum alloys were 6061, which in their conventional form are susceptible to solidification cracking issues. The AM nozzle utilized a novel high-performance modified version of 6061 which exhibits crack resistant properties during the AM process and during welding. When manually conducting GTAWs a filler wire with the same modified version of 6061 was utilized to weld different combinations of 6061 coupons (either modified or unmodified). Due to the grain refinement technology in the modified 6061, either as filler material or base material, there was complete elimination of weld solidification cracking. During EBW development a combination of wrought 6061 with a modified and additively manufactured 6061 was investigated. The EBWs developed exhibited no crack like defects. Each weld development program utilized non-destructive evaluation, metallography, and mechanical testing to determine the final weld acceptance. Mechanical testing involved hardness evaluation and tension testing on welded coupons. Both welding techniques were successfully developed and exhibited adequate properties for the final test articles and met all requirements of the development campaign. These welds were ultimately developed to be utilized on a set of all-aluminum liquid rocket nozzles to demonstrate additively manufactured aluminum alloys for propulsion applications. These aluminum nozzles were tested at NASA Marshall Space Flight Center’s hot fire test facility and subsequently underwent a test campaign involving a variety of chamber pressures and liquid propellant combinations. Following the hot fire test campaign each weldment was investigated for post operation performance and any defects that may have evolved during testing.

Welding↗
NASA NTRS2024

Extreme Temperature Additively Manufactured GRX-810 Alloy Development and Hot-fire Testing for Liquid Rocket Engines

Additive manufacturing (AM) has revolutionized component design for liquid rocket engines by offering rapid manufacturing capabilities. This has led to significant opportunities for development and flight programs in the propulsion industry, resulting in cost and schedule savings, as well as performance improvements through new designs and alloy development. A noteworthy example is the GRX-810 oxide dispersion strengthened (ODS) alloy, which was specifically developed for extreme temperatures. This Ni-Co-Cr based alloy was created using integrated computational materials engineering (ICME) techniques to focus on a new class of materials with exceptional temperature and oxidation-resistant properties. The GRX-810 alloy utilizes AM processes to incorporate nano-scale yttria particles throughout its microstructure, resulting in remarkable enhancements. Compared to traditional Nickel-based superalloys, the GRX-810 alloy offers a two-fold increase in tensile strength, 1,000-fold better creep properties, and two-fold improvement in oxidation resistance. NASA successfully demonstrated the development and manufacturing of components using the GRX-810 alloy through laser powder bed fusion (L-PBF) and laser powder directed energy deposition (LP-DED) processes. Extensive efforts were made to model, evaluate metallurgical properties, develop heat treatment processes, characterize the microstructure, and determine mechanical properties. The GRX-810 alloy was specifically designed for aerospace applications, including liquid rocket engine injectors, preburners, turbines, and hot-section components, capable of withstanding temperatures up to 1,100 °C. The objective of this alloy development is to bridge the temperature gap between traditional Nickel-based superalloys and refractory alloys. This paper provides a comprehensive comparison of the GRX-810 alloy with other aerospace alloys, discussing its microstructure, mechanical properties, processing advancements, component development, and hot-fire testing results. The ultimate goal of this development was to elevate the Technology Readiness Level (TRL) of the GRX-810 alloy, enabling its integration into NASA and commercial aerospace applications.

GRX-810↗
NASA NTRSDate not supplied

Having a Come-Apart: Lessons Learned from Additively Manufactured Hardware Failures

NASA has been engaged with additively manufactured (AM) process and component development since the 2000’s. AM offers various technical advantages, such as enhanced hardware design complexity, part consolidation, and processing of novel alloys in addition to programmatic advantages for reduction in processing time and cost. The focus of much of the AM development at NASA has been to mature the various processes, characterize material properties, develop standards, produce demonstrator parts, and integrate AM hardware in liquid rocket engines. These aspects have been demonstrated through process and design iterations using a methodical characterization, test-fail-fix cycles, as well as application and dissemination of lessons learned. In addition to these fundamental demonstrations of the AM process and hardware development, alloys that provide performance advantages in the high temperature and high-pressure environments have been matured for use in rocket engines. These environments are challenging for any alloy and any design, and the AM process is required to fully meet the intended design requirements. The importance of proper AM process was made evident in the failure of a Laser Powder Bed Fusion (L-PBF) copper-alloy combustion chamber during a hot-fire test due to a degraded material quality resulted from an AM process issue. The hot-fire test aimed to demonstrate high duty cycle under a risk-tolerant development project, where consequences of component failure would be minimal. However, the unintentional component failure emphasized the necessity of robust material characterization and rigorous process control procedures for the safe use of AM components in critical applications. In part, such concerns motivate the AM certification approach that NASA has recently adopted in NASA-STD-6030 “Additive Manufacturing Requirements for Spaceflight Systems”. This presentation provides an overview of the previously mentioned failure, a discussion on the evaluation of the failed chamber and supplemental chambers produced at the same time, a representative material samples that included intentional build witness lines, and a summary of the key results and recommendations from the evaluations. NASA continues to approach AM processes and designs with a level of risk and acceptance of failures that is appropriate for the project objectives, with the overall goal of safe implementation of AM technology and transferring AM technology into commercial space applications. The objective of this presentation is to provide awareness to the community working critical and non-critical AM components and the lessons learned on proper implementation of AM.

Additive Manufacturing↗
NASA NTRSDate not supplied

High Performance Rotating Detonation Rocket Engine for Mars Interplanetary Transport

NASA has successfully evaluated the performances and survivability of two additively manufactured (AM) continuously rotating detonation cycle rocket engine (RDRE) thrust chambers. The AM hardware was subjected to long duration continuous detonative environments in excess of 100 seconds. Performance trends were directly compared to theory and similar scale constant pressure engines with identical propellants. The performance benefits of RDREs include higher combustion efficiency at a more compact design trade space, which allow advantages for future NASA missions. A major finding of this work is that the heat fluxes experienced are substantially higher than traditional liquid rocket engines at the same operating conditions. In addition, completion of combustion occurs rapidly in an annular geometry at ¼ that of the L* and L’ of an equivalent state-of-the-art thrust chamber. Finally, all hardware survived the extreme environments and achieved the major goal of the test project by demonstrating hot fire conditions with detonation modes up to 133 seconds in duration. Follow-on efforts funded by STMD Early Career Initiative (ECI) award are now focused on achieving higher performances than the previous designs and closing the remaining technology risks.

Thomas Teasley↗
NASA NTRSDate not supplied

Al6061-RAM2 Development and Hot-Fire Testing using Additive Manufacturing Laser Powder Directed Energy Deposition for Liquid Rocket Engine Channel-Cooled Nozzles

Aluminum 6061-RAM2 is a high-strength aluminum feedstock developed for additive manufacturing (AM)processes. This alloy leverages Reactive Additive Manufacturing (RAM) technology. The RAM aluminum alloys were developed to be weldable—therefore printable—while equaling or exceeding strength properties of high strength wrought aluminum alloys. NASA and industry partners developed Laser Powder Directed Energy Deposition (LP-DED)additive manufacturing of Al6061-RAM2 for use in aerospace applications. Efforts included establishing build parameters, characterizing the alloy, fabricating components, and completing hot-fire testing of complex internal channel-cooled nozzles. These efforts are to address the growing need for large-scale parts using high-performance light-weight materials. Two rocket engine nozzles were fabricated using LP-DED Al6061-RAM2 that included integral cooling channels. The Al6061-RAM2 has completed process development and initial properties were established. This paper provides an overview of the LP-DED process development, material characterization and properties, component manufacturing, supplemental development, and hot-fire testing. Results from hot-fire testing are provided for a lander-class 31kN (7,000lbf) thrust engine using Liquid Oxygen (LOX)/Liquid Hydrogen (LH2) and LOX/Methane (LCH4).

Al6061-RAM2↗