Tuesday, August 27, 2019
Chemistry (Metallic glasses) Term Paper Example | Topics and Well Written Essays - 500 words
Chemistry (Metallic glasses) - Term Paper Example In particular multicomponent metals, the phase transformation from super cooled liquid to crystalline phase is retarded by orders of 8 to 9. The high glass forming ability, castability, printability and unique characteristics of glassy alloys extend applications when compared to the conventional crystalline alloys. Table 1 gives examples of glassy alloys and when they were first reported. The highest glass forming ability is achieved at compositions near the multicomponent eutectic point with the lowest melting point and is evaluated based on thermal stability parameters of reduced glass transition interval of super cooled liquid region (Inoue, Wang and Zhang, 3). It is reported that the tensile strength of bulk glassy alloys is higher than that of crystalline alloys of the same youngââ¬â¢s modulus whereas their youngââ¬â¢s modulus is a third as high as crystalline alloys of the same tensile strength. Alloy systems are classified as ferrous and nonferrous (Table 3 and Table 1). The discovery and development of bulk glassy alloys were based on research on alloys that bore the three component rules for the stabilization of super cooled liquid. The first rule is the need for a multicomponent that consists of more than three elements. The second is components having atomic mismatches greater than 12% of the three elements, and the third is the negative heat of mixing among the three major components. An excellent linear relationship satisfying Hooks law has also been observed between tensile strength and youngââ¬â¢s modulus (figure 3). The twist angle and shear stress has been found to be 3 times higher than for crystalline alloys. The bulk glassy alloys have high strength reflected by fatigue endurance limits after 107cycles ranging between 0.15 to 0.38 and dynamic durability (Inoue, Wang and Zhang, 4). The endurance of glassy alloys when used as machinery parts has been found
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