1. Inconel 718 & Ti6Al4V Update Status Update Jarrod Smith Jeremy Seidt
Amos Gilat
Dynamic Mechanics of Materials Lab
Department of Mechanical and Aerospace Engineering
The Ohio State University
July 20, 2017

2. Ti6Al4V Status Update Notes: All tests completed up to 2000/s
Temperatures estimated from maximum radiance value in each test
Grounding issue on Ti64 SHB resolved can continue highest rate tests

3. Inco718 & Ti6Al4V – Max Strain vs. Max Temperature
Inconel graph shown during the FAA review meeting reveals odd behavior from the material as it has a smaller increase in temperature at higher strain rates
Investigated Ti6Al4V to better understand the nonphysical results
Ti6Al4V shows almost uniform strain vs. temperature increases which means this beta is not strain rate dependent
However, in Ravichandran’s study the beta in titanium was strain rate dependent
This leads me to believe that the increase in beta in this material is compensating for lower temperatures we are measuring during the test
The lower temperature measurements are caused by a delay in conduction between the bare surface of the specimen and the paint layer
Inconel 718
Ti6Al4V
Ti6Al4V

4. Study of Paint vs. Bare Surface Temperatures
Painted Areas
Bare Areas
Steel specimen tested at ~1000/s Strain Rate
Painted stripes on the specimen and left other areas bare
IR taking images at 45,454 FPS with128x8 resolution
-Bare areas show signs of heating before the central paint strip
As deformation increases, bare areas have higher In-Band Radiance readings and due to their lower emissivity compared to the painted areas the temperature difference is quite significant
Steel: ε~0.55 Paint: ε~0.85
Before localization:
Steel IBR: W/(m^2-sr) Temp: ºC Paint IBR: W/(m^2-sr) Temp: 62.7 ºC
(Paint thickness measured as approx ”)

5. Next Steps
Redo temperature measurements at highest rates using the bare surface of the specimen
Have sufficient number of Ti64 specimens on hand to redo all tests at 0.1, 1, 500, 2000 and ~4000
More inconel samples will have to be machined to redo 500, 2000 and ~4000 tests
Unsure if emissivity of Al2024 samples is high enough to measure temperature differences at highest rates
Could explore other avenues to increase emissivty:
Soot
Higher conductive material