Single-phase rare-earth high-entropy zirconates with superior thermal and mechanical properties

Author(s):  
Xuewei Luo ◽  
Lirong Luo ◽  
Xiaofeng Zhao ◽  
Huangyue Cai ◽  
Shuaishuai Duan ◽  
...  
2021 ◽  
Author(s):  
J. Shi ◽  
Y.W. Zhao ◽  
Chunli Jiang ◽  
Y.Z. Zhang ◽  
Dongli Zou ◽  
...  

2021 ◽  
Vol 22 (4) ◽  
pp. 687-696
Author(s):  
Sachin Rai ◽  
Navin Chaurasiya ◽  
Pramod K. Yadawa

Consequent to the interaction potential model, the high-order elastic constants at high entropy alloys in single-phase quaternary ScTiZrHf have been calculated at different temperatures. Elastic constants of second order (SOECs) helps to determine other ultrasonic parameters. With the help of SOECs other elastic moduli, bulk modulus, shear modulus, Young’s modulus, Pugh’s ratio, elastic stiffness constants and Poisson’s ratio are estimated at room temperature for elastic and mechanical characterization. The other ultrasonic parameters are calculated at room temperature for elastic and mechanical characterization. The temperature variation of ultrasonic velocities along the crystal's z-axis is evaluated using SOECs. The temperature variation of the  average debye velocity and the thermal relaxation time (τ) are also estimated along this orientation axis. The ultrasonic properties correlated with elastic, thermal and mechanical properties which is temperature dependent is also discussed. The ultrasonic attenuation due to phonon – phonon (p-p) interactions is also calculated at different temperatures. In the study of ultrasonic attenuation such as a function of temperature, thermal conductivity appears to be main contributor and p- p interactions are the responsible reason of attenuation and found that the mechanical properties of the high entropy alloy ScTiZrHf are superior at room temperature.


2021 ◽  
pp. 130822
Author(s):  
J. Shi ◽  
Y.W. Zhao ◽  
C.L. Jiang ◽  
X. Wang ◽  
Y.Z. Zhang ◽  
...  

1999 ◽  
Vol 61 (1) ◽  
pp. 31-35 ◽  
Author(s):  
Soichiro Sameshima ◽  
Tatsuhiko Ichikawa ◽  
Manabu Kawaminami ◽  
Yoshihiro Hirata

2021 ◽  
Author(s):  
Baosehng Xu ◽  
Debao LIU ◽  
Baolu SHI ◽  
Liyan GENG ◽  
Yiguang WANG ◽  
...  

Abstract In this work, we have successfully fabricated a novel high-entropy rare-earth zirconate (La0.2Nd0.2Sm0.2Gd0.2Yb0.2)2Zr2O7 (5RE2Zr2O7) ceramics and its counterparts by using a new high-speed grinding strategy combined with typical solid-state reaction method. The X-ray diffraction (XRD) and Raman spectroscopy analysis indicated that the as-prepared 5RE2Zr2O7 ceramics performed single-phase defect fluorite-type structures with highly sintering resistant and excellent thermal stability. The possibility of formation of 5RE2Zr2O7 was verified via first-principles calculations. Meanwhile, the phase structure, thermophysical and mechanical properties of the samples were systematically investigated. The results showed that the 5RE2Zr2O7 ceramics demonstrated lower thermal conductivity (0.9-1.72 W·m-1·K-1) and higher thermal expansion coefficients (10.9 × 10-6 K-1 at 1273 K) than its counterparts. Furthermore, the 5RE2Zr2O7 ceramics presented outstanding mechanical properties including large Young’s modulus (186-257 GPa), higher fracture toughness and lower brittleness index than that of YSZ. Therefore, in view of various excellent properties, the as-prepared 5RE2Zr2O7 ceramics possess great potential for applications in the field of thermal barrier coatings.


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