Microstructural Stability and Strengthening of Additively Manufactured Shape Memory Alloys

Webinar 2

SPEAKER I

Othmane Benafan (NASA Glenn Research Center, USA)

Microstructural stability of shape memory alloys by additive manufacturing-dispersion strengthening

 

Abstract: Shape memory alloys (SMA) are commonly strengthened by solid solution or precipitation strengthening, where the latter is only effective in certain chemistry ranges or at some applicable temperatures. (e.g., Ni-rich NiTi alloy, usage temperatures below precipitate solubility). This study is targeted towards augmenting the need for SMA strengthening via additive manufacturing-dispersion strengthening (AM-DS). This is accomplished by incorporating a fine dispersion of submicron particles such as oxides into a SMA powder followed by additive manufacturing using Laser Powder Bed Fusion (LPBF). This dispersion methods will aid in stabilizing alloys in achieving better dimensional and thermal stability, more effective training procedures, and higher strength. Details of this method, production challenges and preliminary results are presented.

 

Related publications:

  • Othmane Benafan, Glen S. Bigelow, and Darrell J. Gaydosh, “Oxide, Carbide and Nitride Dispersion Strengthening of Shape Memory Alloys and Methods of Making the Same,” U.S. Patent, NASA Case No.: LEW 20059-1 (2022).

SPEAKER II

Ala Qattawi (The University of Toledo, USA)

Additive manufacturing of Fe-based shape memory alloys

 

Abstract: Iron shape memory alloy (Fe-SMA) has outstanding superelasticity and consistent superplastic behavior across a wide temperature range. Alloy systems in the Fe-SMA family can provide a valuable counterpart for NiTi SMA in some applications. However, the viability and impact of manufacturing processing factors on Fe-SMA alloy are not well understood. The current study examines the impact of laser powder bed fusion (LPBF) processing parameters on Fe-Mn-Al-Ni shape memory alloy characteristics such as crack formation, surface roughness, laser-track morphology, density, dimensional accuracy, hardness, and phase transformation. To effectively capture thermal behavior and gather in-situ fabrication data, in-situ monitoring of sample printing was carried out utilizing a unique sensing system made up of a long wave infrared camera throughout a temperature range of −20 °C to 1500 °C.

 

Related publications:

  • Algamal, A, Alhamdi, I, Ali, M, Almotari, A, Gandhi, U, & Qattawi, A. “Additive Manufacturing of Fe-Mn-Al-Ni Shape Memory Alloy: Microstructure and Phase Transformation Characteristics.” Proceedings of the ASME 2023 Conference on Smart Materials, Adaptive Structures, and Intelligent Systems. ASME 2023, Austin, Texas, USA. September 11–13, 2023.
  • Alhamdi I, Algamal A, Almotari A, Ali M, Gandhi U, Qattawi A. Fe-Mn-Al-Ni Shape Memory Alloy Additively Manufactured via Laser Powder Bed Fusion. Crystals. 2023; 13(10):1505. https://doi.org/10.3390/cryst13101505.