Correlation Between Electronic Structure, Mechanical Properties and Stability of TE-TL Metallic Glasses

Mechanical properties (Young\u27s modulus and hardness) of TE-Ni,Cu (TE = Ti, Zr and Hf) amorphous alloys increase approximately linearly with Ni, Cu fraction, x, over a wide composition range (fraction of Ni, Cu atoms ≤ 66 %). This correlates with the observed increase of the Debye temperatures with x and shows that the strength of interatomic bonding increases with x in these alloys. The thermal stability (e.g. the crystallization temperatures) of these alloys also increases with x, thus with increasing interatomic bonding. Since in all these alloys the electronic density of states at the Fermi level, N(EF), decreases linearly with x within the same x-range, a very simple relationship exists between the electronic structure and mechanical and thermal properties. We also estimate the mechanical properties of amorphous TEs (by extrapolating the properties of alloys to x = 0) and compare them with those of crystalline TEs.</p

Electronic structure and properties of (TiZrNbCu)_1-xNi_x high entropy amorphous alloys

A comprehensive study of selected properties of four (TiZrNbCu)_1-xNi_x (x \le 0.25) amorphous high entropy alloys (a-HEA) has been performed. The samples were ribbons about 20 \mum thick and their fully amorphous state was verified by X-ray diffraction and thermal analysis. The surface morphology, precise composition and the distribution of components were studied with a Scanning electron microscope (SEM) with an energy dispersive spectroscopy (EDS) attachment. The properties selected were the melting temperature (T_m), the low temperature specific heat (LTSH), the magnetic susceptibility \chi_exp and the Young^,s modulus (E). Whereas LTSH and \chi_exp were measured for the as-cast samples, E was measured both for as-cast samples and relaxed samples (after a short anneal close to the glass transition temperature). The LTSH showed that the electronic density of states at the Fermi level, N_0(E_F), decreases with increasing x, whereas the Debye temperature (\theta_D) increases with x. This is similar to what is observed in binary and ternary amorphous alloys of early transition metals (TE) with late transition metals (TL) and indicates that N_0(E_F) is dominated by the d-electrons of the TE. The LTSH also showed the absence of superconductivity down to 1.8K and indicated the emergence of the Boson peak above 4K in all alloys.The free-electron like paramagnetic contribution to \chi_exp also decreases with x, whereas E, like \theta_D, increases with x, indicating enhanced interatomic bonding on addition of Ni. The applicability of the rule of mixtures to these and other similar HEAs is briefly discussed

Superconductivity in Bi 2223 compound: physics and potential applications

The main results of the systematic study of the electron transport properties and AC susceptibility in Pb-doped, almost single phase, Bi 2223 ceramic samples and Ag-clad Bi 2223 tape, are presented. Whereas the results for the ceramic samples can only be used for the study of the percolation problem in the weak-link network, those for tape can yield some intrinsic parameters of Bi 2223 compound (the upper critical fields B_C2, the coherence lengths, etc.). In addition, the results for the tape provide some technologically relevant parameters (the pinning potential U_0, volume pinning force F_p and the flux-flow viscosity h) and an insight into the nature of dissipation and pinning in these materials. Some factors limiting the critical current density J_c in the present-day tapes are briefly discussed

Supravodljivost u spoju Bi 2223: fizika i moguće primjene

The main results of the systematic study of the electron transport properties and AC susceptibility in Pb-doped, almost single phase, Bi 2223 ceramic samples and Ag-clad Bi 2223 tape, are presented. Whereas the results for the ceramic samples can only be used for the study of the percolation problem in the weak-link network, those for tape can yield some intrinsic parameters of Bi 2223 compound (the upper critical fields BC2, the coherence lengths, etc.). In addition, the results for the tape provide some technologically relevant parameters (the pinning potential U0, volume pinning force Fp and the flux-flow viscosity h) and an insight into the nature of dissipation and pinning in these materials. Some factors limiting the critical current density Jc in the present-day tapes are briefly discussed.Prikazani su glavni rezultati sustavnog istraživanja električnih svojstava i inicijalne susceptibilnosti gotovo–monofaznih Bi 2223 keramičkih uzoraka dopiranih olovom i srebrom obložene vrpce. Dok se rezultati za keramičke uzorke mogu primjenjivati isključivo za proučavanje perkolacije u sustavu slabih veza, oni za traku daju neke intrinsične parametre Bi 2223 spoja (viša kritična polja i duljine koherencije). Nadalje, rezultati za traku daju neke tehnološki važne parametre (potencijal zapinjanja U0, volumnu gustoću sile zapinjanja Fp i viskoznost tečenja magnetskih vrtloga η) i uvid u prirodu rasipanja energije i zapinjanja vrtloga u tim materijalima. Ukratko su razmotreni razlozi ograničenja kritičnih struja u vrpcama

Vancomycin Graft Presoaking in Anterior Cruciate Ligament Reconstruction Surgery Is Associated with a Lower Risk of Graft Rerupture as Compared With No Vancomycin Presoaking

Background: To determine whether there is any difference in graft rerupture rates and clinical outcomes between cases having vancomycin graft presoaking vs. no vancomycin presoaking in anterior cruciate ligament (ACL) reconstruction (ACLR). Methods: Systematic review and meta-analysis. PubMed, Embase, CINAHL, and Cochrane CENTRAL were searched. Full published studies reporting on the relation between vancomycin graft presoaking and rates of graft rerupture and/or clinical outcomes in ACLR surgery vs. no vancomycin graft presoaking were included. Data extraction and quality appraisal were performed. Meta-analysis was conducted using a random effects model. The study's protocol was prospectively registered with PROSPERO (CRD42021290608). Results: The literature search identified 907 records. After removing duplicates and those not meeting inclusion criteria, 8 studies were included. Meta-analysis showed that the estimated risk of hamstring graft rerupture was lower in cases presoaked with vancomycin vs. those having no presoaking (3.2% vs. 6.2% rerupture rate, risk ratio [RR] = 0.507, 95% CI, 0.39-0.737, p < 0.001). Similarly, the estimated risk of graft rerupture was lower in cases presoaked with vancomycin vs. those having no presoaking when the analysis included various ACL graft types (2.7% vs. 3.9% rerupture rate, RR = 0.557, 95% confidence interval [CI], 0.403-0.771, p < 0.001). Meta-analysis also showed that vancomycin graft presoaking was associated with similar International Knee Documentation Committee scores as compared with no presoaking when looking at hamstring grafts (estimated mean difference 0.112, 95% CI, −2.359 to 2.582, p = 0.929) or when considering various graft types (estimated mean difference 0.933, 95% CI, −0.140 to 2.006, p = 0.088). Conclusion: Vancomycin graft presoaking is a safe practice and does not compromise ACL graft rerupture rates or clinical outcomes

Properties of (TiZrNbCu) 1-x Ni x metallic glasses

International audienc

Vancomycin graft presoaking in anterior cruciate ligament reconstruction surgery Is associated with a lower risk of graft rerupture as compared with no vancomycin presoaking

Background: To determine whether there is any difference in graft rerupture rates and clinical outcomes between cases having vancomycin graft presoaking vs. no vancomycin presoaking in anterior cruciate ligament (ACL) reconstruction (ACLR).Methods: Systematic review and meta-analysis. PubMed, Embase, CINAHL, and Cochrane CENTRAL were searched. Full published studies reporting on the relation between vancomycin graft presoaking and rates of graft rerupture and/or clinical outcomes in ACLR surgery vs. no vancomycin graft presoaking were included. Data extraction and quality appraisal were performed. Meta-analysis was conducted using a random effects model. The study's protocol was prospectively registered with PROSPERO (CRD42021290608).Results: The literature search identified 907 records. After removing duplicates and those not meeting inclusion criteria, 8 studies were included. Meta-analysis showed that the estimated risk of hamstring graft rerupture was lower in cases presoaked with vancomycin vs. those having no presoaking (3.2% vs. 6.2% rerupture rate, risk ratio [RR] = 0.507, 95% CI, 0.39-0.737, p Conclusion: Vancomycin graft presoaking is a safe practice and does not compromise ACL graft rerupture rates or clinical outcomes.Level of Evidence: Level IV. See Instructions for Authors for a complete description of levels of evidence.</p

Structure property relationship in (TiZrNbCu)1−xNix metallic glasses

International audienc