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Metallic glasses exhibit unique mechanical properties. For metallic glass composites (MGC), composed of dispersed nanocrystalline phases in an amorphous matrix, these properties can be enhanced or deteriorated depending on the volume fraction and size distribution of the crystalline phases. Understanding the evolution of crystalline phases during devitrification of bulk metallic glasses upon heating is key to realizing the production of these composites. Here, results are presented from a combination of in situ small‐ and wide‐angle X‐ray scattering (SAXS and WAXS) measurements during heating of Zr‐based metallic glass samples at rates ranging from 102 to 104 Ks−1 with a time resolution of 4ms. By combining a detailed analysis of scattering experiments with numerical simulations, for the first time, it is shown how the amount of oxygen impurities in the samples influences the early stages of devitrification and changes the dominant nucleation mechanism from homogeneous to heterogeneous. During melting, the oxygen rich phase becomes the dominant crystalline phase whereas the main phases dissolve. The approach used in this study is well suited for investigation of rapid phase evolution during devitrification, which is important for the development of MGC. [ABSTRACT FROM AUTHOR]

Better understanding of the nature of magnetic coupling in soft/hard nanocomposites paves the way for tailored exchange-spring magnets. We have investigated a series of amorphous magnetic thin films and trilayers of magnetically soft Co 85 (Al 70 Zr 30) 15 and magnetically hard Sm 12 Co 81 Ti 7 , produced with DC magnetron sputtering. The overall magnetic properties of the trilayers were investigated with focus on the effects of layer configuration and thicknesses on coercivity, originating from the Sm 12 Co 81 Ti 7 phase, and uniaxial in-plane anisotropy induced from the Co 85 (Al 70 Zr 30) 15 phase. In addition, we found that the thermal stability of a 20 nm Sm 12 Co 81 Ti 7 layer was significantly increased if surrounded by two 10 nm Co 85 (Al 70 Zr 30) 15 layers in a trilayer structure. • Properties of trilayers of amorphous hard and soft magnetic phases depend on layer thicknesses. • Uniaxial anisotropy is transferred from soft to hard phases in trilayers. • More pronounced anisotropy with thicker soft layer in hard/soft/hard trilayers. • Stronger coupling between phases in soft/hard/soft samples than in hard/soft/hard. [ABSTRACT FROM AUTHOR]