Phase instability in ZrO2–NiAl functionally graded materials

1997 ◽  
Vol 12 (10) ◽  
pp. 2589-2593 ◽  
Author(s):  
Yi-Rong He ◽  
Vidya Subramanian ◽  
John J. Lannutti
Keyword(s):  
Residual Stress ◽  
Functionally Graded Materials ◽  
Tetragonal Phase ◽  
Room Temperature ◽  
Functionally Graded ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Graded Materials ◽  
Temperature Transformation ◽  
Phase Retention

Sedimentation in organic solvents was followed by hot-pressing to produce 2 mole % yttria stabilized zirconia-NiAl functionally graded materials (FGM's). These FGM's were better able to accommodate high levels of residual stress than alumina-NiAl FGM's; this is possibly due to enhanced tetragonal phase retention. However, we found that the zirconia layer in these FGM's subsequently experiences room temperature transformation of t-ZrO2 to m-ZrO2.

FGMs by Sedimentation

1996 ◽  
Vol 434 ◽  
Author(s):  
Y. He ◽  
V. Subramanian ◽  
J. Lannutti
Keyword(s):  
Residual Stress ◽  
Functionally Graded Materials ◽  
Tetragonal Phase ◽  
Hot Pressing ◽  
Functionally Graded ◽  
Graded Materials ◽  
Al Content ◽  
Strain Behavior ◽  
Phase Retention ◽  
Phase Arrangement

AbstractSimple sedimentation in organic solvents followed by hot-pressing is used to produce alumina-NiAI functionally graded materials (FGMs). Varying degrees of agglomeration influenced the phase arrangement in the mixed layer(s) producing microstructural variation. We discovered a pronounced structural dependence on NiAl stoichiometry. Slight variations in Al content are known to influence Tdb and these apparently lead to large increases in residual stress. Zirconia - NiA1 FGMs were better able to accorrunodate these levels of residual stress possibly due to accommodation by enhanced tetragonal phase retention. However, these FGMs undergo transformation of the tetragonal phase to the monoclinic fonn, starting from the surface. Finally, variable microstructures result in detectable changes in the stress-strain behavior of alumina-NiAl FGMs.

Optimization of the sintering temperature, cooling time and grain size parameters to reduce residual stresses of copper-aluminum functionally graded material using response surface methodology

2021 ◽  
pp. 030932472110687
Author(s):  
Ahmad Gheysarian ◽  
Mohammad Honarpisheh
Keyword(s):  
Residual Stress ◽  
Grain Size ◽  
Residual Stresses ◽  
Functionally Graded Materials ◽  
Sintering Temperature ◽  
Flexible Structures ◽  
Functionally Graded ◽  
Cooling Time ◽  
Property A ◽  
Graded Materials

One of the urgent needs for the medical, aerospace and military industries is to combine materials with heat-resistant as well as flexible structures. To create such a property, a ceramic must be placed next to metal. FGM materials have such a property in terms of thickness. Functionally graded materials (FGM) are examples of materials with different properties in the thickness direction. In the functionally graded materials, different properties can be created, by changing the percent weight of materials in each layer. It is very important to study the number of residual stresses in these materials due to the fact that several materials with different properties are combined with each other. The purpose of this study is to investigate the effect of production parameters on the number of residual stresses in the aluminum-copper FGM part and also to optimize the production process of these materials. The results indicate that the number of residual stresses decreases with increasing the sintering temperature, cooling time of the sample as well as uniformity along the thickness. In the experiments, the maximum residual stress was 171 MPa, which was obtained for a grain size of 100 microns, sintering temperature of 600°C and cooling time of 24 h and the minimum value of pressure residual stress was 120 MPa, which was obtained for grain size of 20 microns, sintering temperature of 900°C and cooling time of 48 h. Also, finite element modeling of the process was performed and shown a good agreement with experimental results.

scholarly journals Correlation Between Hardness and Residual Stress in ZrO2(3Y)/metal Functionally Graded Materials.

1995 ◽  
Vol 42 (12) ◽  
pp. 1384-1388 ◽  
Author(s):  
Mamoru Omori ◽  
Hirotaka Sakai ◽  
Katsuhiro Nishiyama ◽  
Eiji Suzuki ◽  
Toshio Hirai
Keyword(s):  
Residual Stress ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Graded Materials

Evaluation of Fracture Toughness Distribution in Ceramic-Metal Functionally Graded Materials

2007 ◽  
Vol 345-346 ◽  
pp. 497-500 ◽  
Author(s):  
Keiichiro Tohgo ◽  
Hiroyasu Araki ◽  
Yoshinobu Shimamura
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Powder Metallurgy ◽  
Austenitic Stainless Steel ◽  
Functionally Graded Materials ◽  
Stable Crack Growth ◽  
Functionally Graded ◽  
Stabilized Zirconia ◽  
Graded Materials ◽  
Conventional Tests

This paper deals with evaluation of fracture toughness in functionally graded materials (FGMs) consisting of partially stabilized zirconia (PSZ) and austenitic stainless steel SUS 304. FGMs and non-graded composites (non-FGMs) with fine and coarse microstructures are fabricated by powder metallurgy using PSZ and two kinds of SUS 304 powders. The fracture toughness is determined by conventional tests for several non-FGMs with each material composition and by a method utilizing stable crack growth for FGMs. Based on the experimental results, fracture mechanism, influences of microstructure on fracture toughness, and difference in fracture toughness between the FGMs and non-FGMs has been discussed.

Dynamic Analysis with Stress Recovery for Functionally Graded Materials: Numerical Simulation and Experimental Benchmarking

2014 ◽  
Vol 2 (1) ◽  
pp. 21
Author(s):  
Carlos Alberto Dutra Fraga Filho ◽  
Fernando César Meira Menandro ◽  
Rivânia Hermógenes Paulino de Romero ◽  
Juan Sérgio Romero Saenz
Keyword(s):  
Numerical Simulation ◽  
Dynamic Analysis ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
Stress Recovery ◽  
Graded Materials
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