Publication Date:
2016-10-13
Description:
We report the experimental observation of an increase in the elastic anisotropy of tungsten upon He-ion implantation, probed optically using transient grating spectroscopy. Surface acoustic wave (SAW) velocity measurements were performed on a (110) oriented tungsten single crystal as a function of in-plane propagation direction for unimplanted and implanted samples. Our measurements allow us to finely resolve the remarkably small elastic anisotropy of the samples investigated. SAW velocity calculations are used to interpret the experimental data and to extract the Zener anisotropy parameter η and the elastic constant C 44 . Upon ion implantation, we observe an increase in the quantity ( η − 1 ) by a factor of 2.6. The surprising increase in elastic anisotropy agrees with previous theoretical predictions based on ab initio calculations of the effect of self-interstitial atoms and He-filled vacancy defects on the elastic properties of tungsten.
Print ISSN:
0003-6951
Electronic ISSN:
1077-3118
Topics:
Physics
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