Making glassy solids ductile at room temperature by imparting flexibility into their amorphous structure

<p>Making glasses ductile at room temperature is a daunting challenge, but has been shown to be feasible in recent years. We explain the plastic flow from the standpoint of the flexibility available in the amorphous structure: imparting flexibility into the structure facilitates bond switching needed to mediate shear transformations to carry strain. This structure–property correlation is demonstrated using molecular dynamics simulation data. The flexibility can be improved via ultrafast quench or rejuvenation. In particular, the flexibility volume parameter offers a quantitative metric to explain the flexibility and deformability, even for glasses where the commonly cited free volume is not applicable.</p> <p>This Perspective demonstrates using examples and models that it is the flexibility rather than the excess volume that can be tuned to facilitate plastic flow and ductility in glassy materials.</p

Philosophie ; vol. 1, no 1

18 pages.Collaborateurs : Simard, Michel ; Lachance, Louis ; Martinelli, Lucien ; Lacroix, Benoît ; Roy, Jean ; Tousignant, Pierre ; Soeur Marie-Aimé ; Brochu, Jacques

Mean differences of perceived time distortion and p values of pairwise comparisons in Experiment 4.

<p>Note: *** p<.001.</p><p>Mean differences of perceived time distortion in Experiment 4 (Bonferroni corrected pairwise comparisons) indicating that the perceived time distortions of 1L and 2Ls conditions were significantly different from those of 3Ls and 4Ls conditions.</p

Experimental approach and results of Experiment 1b (the working memory experiment).

<p><b>A</b>, Experimental approach of the working memory experiment (an exemplary trial of set size = 5). <b>B,</b> The mean Cowan’s Ks of each set size condition in the working memory experiment. <b>C,</b> Individual’s working memory capacity was not significantly (p>.27) correlated with his or her spatial capacity of multi-temporal processing. Error bars are within-subjects SEs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091797#pone.0091797-Cousineau1" target="_blank">[64]</a>.</p

Mean K value differences and p values of pairwise comparisons in Experiment 1a.

<p>Note: *p<0.05, ***p<.001.</p><p>Mean K value differences in Experiment 1a (Bonferroni corrected pairwise comparisons), indicating that K values of set size 5, 7 and 9 were not significantly different from each other. However, these K values were all significantly larger than those of set size 1 and 3.</p

Experimental approach and results of the oddball duration experiment.

<p><b>A</b>, Experimental approach of the oddball duration experiment. <b>B,</b> Results of the oddball duration experiment. Black squares are mean correctness of 20 participants. Red circles are correctness data from a single participant who had the maximum odd ball duration corresponding to 95% correctness (denoted by a blue diamond) after fitted by a sigmoid model (green curve). Error bars are within-subjects SEs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091797#pone.0091797-Cousineau1" target="_blank">[64]</a>.</p

Percentages of correct responses of each set size condition in Experiment 1a (N = 29; red circles) and Experiment 2 (N = 21; green squares) and their linear regression curves.

<p>The red curve is for Experiment 1a (slope = −0.034; R² = 0.979; F(3, 1) = 139.227; p<.002) and the green curve for Experiment 2 (slope = −0.028; R² = .941; F(3, 1) = 47.739; p<.007). Error bars are within-subjects SEs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0091797#pone.0091797-Cousineau1" target="_blank">[64]</a>. The slope of regression curve in Experiment 1a was not significant different from the slope of regression curve in Experiment 2 (Independent samples t-test; t(48) =  −1.397; p = .169), suggesting the percentages of correct responses in both experiments obeyed a Weber’s law.</p