Structural characterisation of Cu-Zr thin film combinatorial libraries with synchrotron radiation at the limit of crystallinity

We report for the first-time combinatorial synthesis of thin film metallic glass libraries via magnetron co-sputtering at the limit of crystallinity. Special care was taken to prepare extremely pure CuZr films (1–2 µm thickness) with large compositional gradients (Cu18.2Zr81.8 to Cu74.8Zr25.2) on X-ray transparent polymer substrates in high-vacuum conditions. Combined mapping of atomic structure (synchrotron radiation) and chemical composition (X-ray fluorescence spectroscopy) revealed that over the entire composition range, covering multiple renowned glass formers, two phases are present in the film. Our high-resolution Synchrotron approach identified the two phases as: untextured amorphous Cu51Zr14 (cluster size 1.3 nm) and textured, nanocrystalline α-Zr (grain size 1–5 nm). Real space HR-STEM analyses of a representative composition substantiate our XRD results. Determined cluster and grain sizes are below the resolution limit of conventional laboratory-scale X-ray diffractometers. The presented phase mixture is not permitted in the Cu-Zr phase diagram and contrary to existing literature. The phase ratio follows a linear trend with amorphous films on the Cu-rich side and increasing amounts of α-Zr with increasing Zr content. While cluster size and composition of the amorphous phase remain constant thorough the compositional gradient, crystallite size and texture of the nanocrystalline α-Zr change as a function of Zr content.publishedVersionPeer reviewe

Thermopower and hardness characterization of structural relaxation and crystallization in FINEMET type amorphous precursor alloy

In this paper, the thermopower (U) and hardness (HV) of FINEMET type glasses are studied during structural relaxation and beyond the crystallization onset. In this multicomponent alloy (Fe_{73.5-x}Si_{13.5}B_{9}Nb_{x}Cu_{1}) both property changes are more complex than that in binary Fe-B glasses. The phenomenon of relaxation and the crystallization onset can be successfully distinguished in both property changes. Simultaneously with the hardness increase, a slope increase in the thermopower versus temperature dependences was observed if crystallization started. The character of both property changes does alter drastically at the beginning of amorphous-nanocrystalline transformation. Similar trends were measured on samples undergoing traditional isothermal and pulse heat treatments

Radiographic signs for detection of femoroacetabular impingement and hip dysplasia should be carefully used in patients with osteoarthritis of the hip

BACKGROUND: During the last years, terms like acetabular retroversion, excessive overcoverage, and abnormal head-neck-junction with the so called “pistol-grip-deformity” has been added to the classical description of hip dysplasia. These anatomical changes could lead to a femoroacetabular impingement (FAI). Both kinds of FAI has been indentified as a main reason for hip pain and progressive degenerative changes leading to early osteoarthritis of the hip. A lot of radiographic criteria on pelvic views have been established to detect classical dysplasia and FAI. The present study was initiated to assess the hypothesis that age and severity of osteoarthritis affect measurements of different radiographic parameters. METHODS: The pelvic radiographs of 1614 patients were measured for head-ratio, CE-angle, roof obliquity, extrusion-index, depth-to-width ratio, CCD-angle, sharp’s angle. To evaluate the severity of osteoarthritis of the hip the classification by Kellgren and Lawrence was used. Associations between age and radiographic parameters or severity of osteoarthritis were assessed by Spearman’s (ρ) or Kendall’s (r) rank correlation coefficient, respectively. RESULTS: 366 (22.7%) patients presented no sign of osteoarthritis, 367 (22.7%) patients presented I° osteoarthritis, 460 (28.5%) patients presented II° osteoarthritis, 307 (19%) III° osteoarthritis and 114 (7.1%) IV° osteoarthritis of the hip. The mean head-ratio of all patients was 1.13 ± 0.26 (0.76 – 2.40), the mean CE-angle 40.05° ± 10.13° (0° - 70°), the mean roof obliquity was 35.27°± 4.96° (10° – 55°), the mean extrusion-index was 12.99 ± 9.21 (6.20 – 95.2), the mean depth-to-width ratio was 59.30 ± 8.90 (6.30 – 100), the mean CCD-angle was 127.68° ± 7.22° (123° – 162°) and the mean sharp’s angle was 9.75° ± 5.40° (1° - 34°) There was a weak association between age and the severity of osteoarthritis of the hips (left: r = 0.291; right: r = 0.275; both P < 0.001) with higher osteoarthritis levels observable for elderly patients). CONCLUSION: Severity of osteoarthritis has a negative impact on measurements of different radiographic parameters. Therefore - in our opinion - epidemiological studies on prearthrotic deformities should only be performed in healthy adults with no signs of osteoarthritic changes