【作者】 欧阳高勋；

【导师】 谭敦强；

【作者基本信息】 南昌大学 ， 材料学， 2008， 硕士

【摘要】 喷射沉积技术是制备高性能大尺寸快速凝固镁合金的有效方法。采用喷射沉积技术制备的镁合金具有晶粒细小、组织均匀等特点,与传统铸造镁合金相比,大幅提高了力学和耐腐蚀性能,与粉末冶金镁合金相比,缩短了工艺流程。喷射沉积制备新型镁合金具有理论和应用价值。本文主要针对Mg-Al-Zn和Mg-Zn-Zr系列变形镁合金,研究以氮气为雾化气体制备的喷射沉积镁合金材料,分析喷射沉积坯的显微组织和物相组成,研究沉积坯经均匀化退火和和挤压棒材经T5、T6处理后合金的显微组织和性能变化,分析不同Nd含量对喷射沉积镁合金Mg-Al-Zn系合金显微组织和力学性能的影响。研究结果表明:喷射沉积工艺制备的镁合金材料有少量的孔隙,热挤压后获得致密的镁合金棒材。镁合金Mg-7Al-4.5Ca-1.5Zn-1Nd沉积态的物相组成是a-Mg和少量的Al₂Ca,挤压后物相组成基本没有发生变化。挤压后T5处理（160℃/8h）硬度值是99.7Hv,T6处理（固溶400℃/1h+时效180℃/6h）硬度值是100.3Hv。Mg-Al-Zn-Ca系合金中加入不同含量的Nd,合金挤压态的硬度和抗拉强度都有所提高,当Nd含量为2%时,合金的力学性能最佳。镁合金Mg-6Zn-6Ca-0.6Zr沉积态的物相组成主要a-Mg、MgZn₂、Mg₂Ca和Mg₆Zn₃Ca₂,挤压态试样物相组成主要为a-Mg、MgZn₂和Mg₂Ca。挤压态T5处理（180℃/6h）时效硬度为98.6Hv,抗拉强度为367.1MPa;T6处理（固溶400℃/1h+时效180℃/6h）硬度为99.5Hv,抗拉强度为369.3MPa。更多还原

【Abstract】 Spray deposition technology is an effective way to prepare high-performance large-size rapidly solidified magnesium alloys.The magnesium alloys prepared by spray deposition technique have fine crystal grains and structural homogeneity. Compared with casting technology,spray deposition technology can greatly increase mechanical properties and corrosion resistance of magnesium alloys.Compared with power metallurgy technology,Spray deposition technology can short process flow of preparing magnesium alloy.Spray deposition preparing a new type of magnesium alloy has theoretical and practical values.This paper took Mg-Al-Zn and Mg-Zn-Zr alloys prepared by pure industrial nitrogen as research objects.The microstructure and phrases of spray deposited billets were analyzed.The microstructure and property changes of spray deposited magnesium alloys under the action of homogenizing annealing and heat treatment were researched.The effects of addition of Nd on the microstructures and properties of spray deposited Mg-Al-Zn alloys were analyzed.The experimental results showed that there were a few porosities in spray deposited magnesium alloys and the bars of magnesium alloy via hot extrusion appeared more compact than the deposit performs of that.The major phase composition of the deposit perform of Mg-7Al-4.5Ca-1.5Zn-1Nd alloy were a-Mg and a small amount of Al₂Ca,and the phases composition of as-extruded alloy were the same as the deposit perform.The hardness of as-extruded Mg-7Al-4.5Ca-1.5Zn-1Nd alloy was 99.7 Hv at T5 treatment（160℃/8 h）,and that was 100.3 Hv at T6 treatment（425℃/1 h+160℃/8 h）.The addition of Nd into Mg-Al-Zn alloys affected the microstructure and property of that.Both hardness and tensile strength of as-extruded alloys differently got increases.When the content of Nd was 2%,the mechanical properties of as-extruded Mg alloy were best.The major phase composition of the deposit perform of Mg-6Zn-6Ca-0.6Zr alloy were a-Mg, MgZn₂,Mg₂Ca and Mg₆Zn₃Ca₂.After hot extruded,the major phase composition of sample included a-Mg、MgZn₂ and Mg₂Ca.The hardness of the as-extruded sample was 98.6 Hv when it was aged at T5 treatment（180℃/6 h）,and the tensile strength of that was 367.1 MPa and the hardness of the as-extruded sample at T6 treatment （425℃/1 h+160℃/8 h） was 99.5Hv,and the tensile strength of that was 367.1 MPa.更多还原