Ultrasonic Additive Manufacturing of Metal-Matrix Shape Memory Composites

Author(s):  
Ryan Hahnlen ◽  
Jennifer L. Morris ◽  
Marcelo J. Dapino
Author(s):  
Ryan Hahnlen ◽  
Marcelo J. Dapino

Shape memory and superelastic NiTi are often utilized for their large strain recovery and actuation properties. The objective of this research is to utilize the stresses generated by pre-strained NiTi as it is heated in order to tailor the CTE of metal-matrix composites. The composites studied consist of an Al 3003-H18 matrix with embedded NiTi ribbons fabricated through an emerging rapid prototyping process called Ultrasonic Additive Manufacturing (UAM). The thermally-induced strain of the composites is characterized and results show that the two key parameters in adjusting the effective CTE are the NiTi volume fraction and prestrain of the embedded NiTi. From the observed behavior, a constitutive composite model is developed based constitutive SMA models and strain matching composite models. Additional composites were fabricated to characterize the NiTi-Al interface through EDS and DSC. These methods were used to investigate the possibility of metallurgical bonding between the ribbon and matrix and determine interface shear strength. Interface investigation indicates that mechanical coupling is accomplished primarily through friction and the shear strength of the interface is 7.28 MPa. Finally, using the developed model, a composite was designed and fabricated to achieve a near zero CTE. The model suggests that the finished composite will have a zero CTE at a temperature of 135°C.


Author(s):  
Phillip Evans ◽  
Marcelo Dapino ◽  
Ryan Hahnlen ◽  
Joshua Pritchard

High performance optical metering structures in airborne and space applications need to exhibit dimensional stability in demanding thermal and mechanical environments. Materials for this application should have a low coefficient of thermal expansion, high thermal diffusivity, high specific stiffness and exhibit good ductility. Current materials are limited in one or more of these properties. Common choices are invar, carbonfiber composite, and silicon-carbide. The former has low specific stiffness and thermal diffusivity and the latter choices are brittle materials that require special care and have slow manufacturing processes. In this work, the development of a thermally invariant metal matrix composite will be described along with its incorporation into a high performance optical metering structure. The material is a composite of super-elastic NiTi ribbons and aluminum, where the ribbons are embedded using ultrasonic additive manufacturing. Measurements and modeling of the thermo-elastic response will be presented followed by the design and manufacture of a metering structure. The metering structure design eases integration with an optical bench and lens bezels while leveraging the advantageous properties of this new metal matrix composite.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4254
Author(s):  
Paulina A. Quiñonez ◽  
Leticia Ugarte-Sanchez ◽  
Diego Bermudez ◽  
Paulina Chinolla ◽  
Rhyan Dueck ◽  
...  

The work presented here describes a paradigm for the design of materials for additive manufacturing platforms based on taking advantage of unique physical properties imparted upon the material by the fabrication process. We sought to further investigate past work with binary shape memory polymer blends, which indicated that phase texturization caused by the fused filament fabrication (FFF) process enhanced shape memory properties. In this work, two multi-constituent shape memory polymer systems were developed where the miscibility parameter was the guide in material selection. A comparison with injection molded specimens was also carried out to further investigate the ability of the FFF process to enable enhanced shape memory characteristics as compared to other manufacturing methods. It was found that blend combinations with more closely matching miscibility parameters were more apt at yielding reliable shape memory polymer systems. However, when miscibility parameters differed, a pathway towards the creation of shape memory polymer systems capable of maintaining more than one temporary shape at a time was potentially realized. Additional aspects related to impact modifying of rigid thermoplastics as well as thermomechanical processing on induced crystallinity are also explored. Overall, this work serves as another example in the advancement of additive manufacturing via materials development.


2021 ◽  
Vol 419 ◽  
pp. 129437
Author(s):  
Chen Yang ◽  
Rui Zheng ◽  
Muhammad Rizwan Younis ◽  
Jundong Shao ◽  
Lian-Hua Fu ◽  
...  

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