DSpace collection: 期刊論文

Zr-based metallic glass thin film coating for fatigue-properties improvement of 7075-T6 aluminum alloy

title: Zr-based metallic glass thin film coating for fatigue-properties improvement of 7075-T6 aluminum alloy abstract: 摘要： In order to improve the fatigue life of high strength aluminum alloy, a protection coating with 200nm Zr-based metallic glass thin film (MGTF) coupled with 50nm titanium thin film buffer layer was coated on the 7075-T6 aluminum alloy by DC sputtering. The results of four-point-bending fatigue test revealed that the fatigue life of 7075-T6 aluminum alloy with Zr-based MGTF could be improved by 30 times at a stress level of 250MPa. The improvement of Zr-based MGTF coated samples in fatigue limit was 235MPa (56.7% increase) in comparison with 150MPa for the uncoated samples. The superior mechanical properties of Zr-based MGTF, such as high strength and good bending ductility, lower surface roughness, good adhesion between the film and the substrate, and high compressive residual stress are the key factors to improve the fatigue resistance of the coated aluminum alloy. •Metallic glass thin film (MGTF) coatings sputtered on high strength aluminum alloy.•30-Time improvement of fatigue life of MGTF-coated samples at 250MPa.•Fatigue limit of MGTF-coated samples is 56% higher than the bare one.•Lower surface roughness plays an important role to improve fatigue life.•Compressive residue stress is the key to restrict fatigue cracks. 出版者： Amsterdam: Elsevier B.V 出版日期： 2013-10-01 出處： Thin solid films, 2013-10, Vol.544, p.331-334 版權： 2013 Elsevier B.V. 版權： 2014 INIST-CNRS 識別號： ISSN: 0040-6090 識別號： EISSN: 1879-2731 識別號： DOI: 10.1016/j.tsf.2013.02.104 識別號： CODEN: THSFAP

Zr-based metallic glass thin film coating for fatigue-properties improvement of 7075-T6 aluminum alloy

ZnxCd1-xS quantum dots-based white light-emitting diodes

title: ZnxCd1-xS quantum dots-based white light-emitting diodes abstract: 出版日期： 2013-06-15 出處： Optics letters, 2013-06, Vol.38 (12), p.2080 資源來源： Optica Publishing Group Journals 識別號： ISSN: 0146-9592 識別號： EISSN: 1539-4794 識別號： DOI: 10.1364/OL.38.002080

Viscous flow and thermoplastic forming ability of a Zr-based bulk metallic glass composite with Ta dispersoids

title: Viscous flow and thermoplastic forming ability of a Zr-based bulk metallic glass composite with Ta dispersoids abstract: 摘要： Compressive flow stress clearly decreases with lower compressive strain rate as well as higher compression temperature, as shown in (a) The lowest flow stress, 76MPa, can be obtained at 764K with strain rate of 5×10−2s−1. A submicron-scaled hologram pattern was replicated by hot pressing the Zr-based BMGC plate against a die engraved with submicron-scaled groove at 756K as illustrated in (b). The enlarged SEM image of the replicated hologram pattern in (c) shows grooves about 0.6μm in depth, indicating relatively good microforming ability for this Zr47.3Cu32Al8Ag8Ta4Si0.7-based BMGC in the SCL region. [Display omitted] ► Deformation behavior of the Zr-based BMGC within the SCL region reveals that a relatively low viscosity between 108 and 1010Pas. ► More than 60% plastic strain can be obtained readily by compression test at the temperatures within SCL region under different strain rates. ► All evidences of the XRD analysis and TEM characterization confirms that the amorphous phase in Zr4-based BMGC would keep stable after hot compression. ► A strain rate sensitivity exponent (m) more than 0.35 was measures for the Zr-based BMGC deformed at 756K, and 764K. ► The imprinted hologram pattern with 0.6μm depth grooves demonstrates relatively good microforming ability for this Zr-based BMGC. The thermoplastic deformation behavior of a Zr47.3Cu32Al8Ag8Ta4Si0.7-based bulk metallic glass composite (BMGC) is studied using thermal mechanical analyzer (TMA) and high temperature compression test in the supercooled liquid (SCL) region. The deformation behavior of the Zr47.3Cu32Al8Ag8Ta4Si0.7-based BMGC rod is investigated using TMA under compression at different strain rates (5×10−2 to 5×10−1s−1) and at different temperatures above the onset temperature of viscous-flow (∼740 to 764K) in the SCL region. It is observed that, at a constant strain rate of 5×10−2s−1, the flow stress decreases with increasing temperature and reaches a relatively low value about 76MPa at 764K. In parallel, the value of flow stress increases with increasing strain rate at the same testing temperature. A satisfactory thermoplastic forming ability of the Zr47.3Cu32Al8Ag8Ta4Si0.7-based BMGC in the SCL region is demonstrated by imprinting the hologram pattern. 出版者： Kidlington: Elsevier B.V 出版日期： 2012-09-25 出處： Journal of alloys and compounds, 2012-09, Vol.536, p.S165-S170 版權： 2012 Elsevier B.V. 版權： 2015 INIST-CNRS 識別號： ISSN: 0925-8388 識別號： EISSN: 1873-4669 識別號： DOI: 10.1016/j.jallcom.2012.01.020