Study On The Synthesis And Its Performance Of Mg-based Metallic Glasses By Mechanical Alloying

MgNi, Mg2Ni, Mg₄₅Ni₅₀Ti₅, Mg₄₅Ni₅₀Al₅, Mg₅₅Ni₃₅Si₁₀ and Mg₆₅Cu₂₅Gd₁₀ alloys which are light with low price and good glass forming ability, were synthesized in the present work by mechanical alloying (MA). The thermodynamics and anticorrosion performance of amorphous powders have been investigated by XRD, DSC and electrochemistry test.In the first part of the dissertation, the development, application and problems of Magnesium alloy have been introduced, then, a historic progress of metallic glass over past 40 years has been critically overviewed, which includes the develop history, excellent properties, wide applications and preparation technique. Good performance of Mg-based bulk metallic glass (BMGs) and its bright future for application were introduced especially, it's historic progress and preparation technique were summarized. Based on investigation actuality, the objective and significance of this dissertation were proposed.The following research results about the dissertation were obtained:Influence of milling condition on milling efficiency was investigated, the optimum condition was found. The optimum technological condition of ball mill was as follows: the rotation speed was 600rpm, ball to powder ratio was 20:1. The process of mechanical alloying of elemental powder mixtures have studied by means of XRD in this dissertation. The results indicated that corresponding amorphous compounds have been obtained by mechanical alloying.In this dissertation, the thermal stability and crystallization kinetics of magnesium amorphous alloy have been systematically investigated by DSC. Crystallization process of Mg₅₅Ni₃₅Si₁₀, Mg₄₅Ni₅₀Al₅, Mg₄₅Ni₅₀Ti₅ and Mg₆₅Cu₂₅Gd₁₀ alloy were studied when heating by use of Kissinger equation. The results show that the dynamics effect exists in the crystallization process. Mg₅₅Ni₃₅Si₁₀ have best thermal stability, next, Mg₄₅Ni₅₀Al₅, Mg₄₅Ni₅₀Ti₅ and Mg₆₅Cu₂₅Gd₁₀ have good thermal stability also.Amorphous powders' corrosion potentials have been got by electrochemistry experiment. Through compared with of AZ31 and AZ61 it's finds that Mg-based amorphous powders have good corrosion resistance performance.