Issue 48, 2021

Effect of the growth pulling direction on 3D anisotropic stress during different stages of semitransparent Li2MoO4 growth

Abstract

The three dimensional thermal stress field was calculated for different growth stages of a Li2MoO4 (LMO) crystal grown in an inductively heated Czochralski furnace using the anisotropy and temperature-dependent mechanical properties. Four pulling directions were considered, including [100], [010], [001] and [110]. The elastic and thermal expansion matrices corresponding to a, b and [110] directions are computed by a tensor transformation method from the available experimental coefficients characterizing the LMO crystal pulled along the c-direction. The crystal–melt interface convexity and the input heat power obtained numerically for the final growth stage meet the experimental values for the absorption coefficient close to 0.2 cm−1. Compared to an assumed opaque case, von Mises stress increases strongly at the semitransparent LMO interface due to the internal radiative heat transfer inside the crystal which leads to a large convexity of the crystal–melt interface. The thermal stresses for the [100] and [010] pulling growth directions were the same since they present the same crystallographic axes and are larger than the c-pulling case, especially for the earlier stages where the increase rate is about 36%. Three and two-fold symmetries are shown for c and a (or b) pulling cases, respectively, in the distribution of von Mises stress at a cross section of the LMO crystal. Thermal stresses along the [110] direction were almost the same compared to the [100] and [010] pulling axes with two-fold symmetries. The gas convection and temperature dependence of the mechanical properties have an important effect on the thermal stress values and distributions and have be taken into account in accurate computation of the stress field.

Graphical abstract: Effect of the growth pulling direction on 3D anisotropic stress during different stages of semitransparent Li2MoO4 growth

Article information

Article type
Paper
Submitted
10 iyn 2021
Accepted
12 avq 2021
First published
20 avq 2021

CrystEngComm, 2021,23, 8612-8621

Effect of the growth pulling direction on 3D anisotropic stress during different stages of semitransparent Li2MoO4 growth

Y. Z. Bouzouaoui, F. Mokhtari, M. Velázquez, S. Zermout and I. Lasloudji, CrystEngComm, 2021, 23, 8612 DOI: 10.1039/D1CE00766A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements