5513.001 Thermal Aging Study for Additively Manufactured F357 Aluminum

Problem

There are a number of sustainment critical parts that have historically been produced using titanium alloys for their intermediate use temperature (200 oC to ~500 oC) specific strength. High-strength aluminum alloys such as F357 make it possible to pursue select intermediate temperature (<250 oC) applications such as heat exchangers at substantial cost savings in comparison to titanium alloys. Laser powder bed fusion (LPBF) technology has shown promise in producing various F357 heat exchanger designs. Qualification of these designs requires additional physical and mechanical property data to help understand post-processing and use temperature effects on material microstructure and tensile properties.

Objective

The objective of this program is to accelerate the qualification of LPBF F357 aluminum alloy by quantifying the effects of thermal treatments and service temperatures on material microstructure and performance. These data will play a critical role in certification and qualification of components for the sustainment of legacy defense systems.

Technical Approach

The University of Texas at El Paso (UTEP) is leading the effort. The first phase includes powder acquisition and characterization, material parameter validation, and the building of cubes for material characterization. Multiple post-processing techniques for heat treatment are being investigated. Tensile samples are manufactured using EOS M290 and SLM M280 systems in the Z and XY orientations. Specimens are tested in several conditions including as built, T6, HIP, and HIP +T6 states. Subsequently, 100 and 1000 hours of exposure at an aging temperature of 350°F are being studied.

Project Participants

Project Principal

Other Project Participants

• Air Force Research Laboratory

Public Participants

• U.S. Department of Defense