Functionally graded materials for marine risers by additive manufacturing for high-temperature applications: Experimental investigations

Structures ◽  
2022 ◽  
Vol 35 ◽  
pp. 931-938
Author(s):  
Srinivasan Chandrasekaran ◽  
S. Hari ◽  
Murugaiyan Amirthalingam
Materials ◽  
2017 ◽  
Vol 10 (12) ◽  
pp. 1368 ◽  
Author(s):  
Uwe Scheithauer ◽  
Steven Weingarten ◽  
Robert Johne ◽  
Eric Schwarzer ◽  
Johannes Abel ◽  
...  

Author(s):  
Yuen-Shan Leung ◽  
Huachao Mao ◽  
Yong Chen

Functionally graded materials (FGM) possess superior properties of multiple materials due to the continuous transitions of these materials. Recent progresses in multi-material additive manufacturing (AM) processes enable the creation of arbitrary material composition, which significantly enlarges the manufacturing capability of FGMs. At the same time, the fabrication capability also introduces new challenges for the design of FGMs. A critical issue is to create the continuous material distribution under the fabrication constraints of multi-material AM processes. Using voxels to approximate gradient material distribution could be one plausible way for additive manufacturing. However, current FGM design methods are non-additive-manufacturing-oriented and unpredictable. For instance, some designs require a vast number of materials to achieve continuous transitions; however, the material choices that are available in a multi-material AM machine are rather limited. Other designs control the volume fraction of two materials to achieve gradual transition; however, such transition cannot be functionally guaranteed. To address these issues, we present a design and fabrication framework for FGMs that can efficiently and effectively generate printable and predictable FGM structures. We adopt a data-driven approach to approximate the behavior of FGM using two base materials. A digital material library is constructed with different combinations of the base materials, and their mechanical properties are extracted by Finite Element Analysis (FEA). The mechanical properties are then used for the conversion process between the FGM and the dual material structure such that similar behavior is guaranteed. An error diffusion algorithm is further developed to minimize the approximation error. Simulation results on four test cases show that our approach is robust and accurate, and the framework can successfully design and fabricate such FGM structures.


2003 ◽  
Vol 18 (2) ◽  
pp. 448-455 ◽  
Author(s):  
N. Bertolino ◽  
M. Monagheddu ◽  
A. Tacca ◽  
P. Giuliani ◽  
C. Zanotti ◽  
...  

Self-propagating high-temperature synthesis was used to prepare boride-based functionally graded materials (FGMs) as thermal barriers for space re-entry vehicles. FGMs are characterized by inhomogeneous spatial composition, resulting in different spatial characteristics. In this work, the FGMs were composed of a ceramic [i.e., MB2 (M = Ti, Zr, Hf)] and a metallic (i.e., NiAl) side, joined together by composite layers of graded stoichiometries of the two components. Thus, in the same material, the boride end gives thermal insulation, while the intermetallic end offers an easy junction to the structure of the space aircraft. The prepared FGMs showed good adhesion between the layers and global compactness after preparation and thermal tests. The microhardness along the samples was measured, and their insulating capabilities were evaluated.


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