Defect-induced ordering and disordering in metallic glasses

• Published in: Intermetallics Vol. 163; p. 108041
• Main Authors: Makarov, A.S., Afonin, G.V., Konchakov, R.A., Qiao, J.C., Vasiliev, A.N., Kobelev, N.P., Khonik, V.A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2023
• Subjects: Defects; Disordering; Metallic glasses; Ordering; Relaxation; Shear modulus; Structure factor; Metallic glasses; Structure factor; Relaxation; Shear modulus; Ordering; Disordering; Defects
• ISSN: 0966-9795; 1879-0216
• DOI: 10.1016/j.intermet.2023.108041

On the basis of shear modulus measurements on a Pt-based glass, we calculated temperature dependence of the defect concentration c using the Interstitialcy theory. This temperature dependence is compared with temperature dependence of the normalized full width at half maximum (FWHM) γ of the first peak of the structure factor S(q) for the same glass available in the literature. It is found that γ above the glass transition temperature Tg linearly increases with c in the same way for both initial and relaxed (preannealed) samples providing the evidence of defect-induced disordering in the supercooled liquid region independent of glass thermal prehistory. For both states of the samples, the derivative dγ/dc is close to unity. Below Tg, the interrelation between γ and c is entirely different for initial and relaxed samples. In the former case, strong defect-induced ordering upon approaching Tg is observed while relaxed samples do not reveal any clear ordering/disordering. Possible reasons for these observations are discussed. To further investigate the relationship between the normalized FWHM and defect concentration, we performed molecular dynamic simulation of γ(c)-dependence in a high-entropy FeNiCrCoCu model glass. It is found that γ also linearly increases with c while the derivative dγ/dc is again close to unity just as in the case of Pt-based glass. •Defect concentration c in a Pt-based glass is determined.•It is compared with the width FWHM of the structure factor.•It is found that FWHM is proportional to c above Tg.•Similar situation is shown for FeNiCrCoCu model glass.•It is concluded that disordering is largely related to the defects.