在铸钢坩锅中熔炼制备了Mg-2Nd二元镁合金,试样经不同热处理工艺处理后,测试合金的室温拉伸性能,采用光学显微镜(OM)、扫描电镜(SEM)及透射电镜(TEM)观察合金的显微组织,通过X射线衍射法(XRD)和能谱分析(XEDS)及选区电子衍射花样进行合金中的物相鉴别和微观成分分析.结果表明:Mg-2Nd合金的铸态组织由α-Mg基体和呈离异共晶形貌的Mg12Nd相组成;热挤压后,Mg12Nd相沿挤压方向呈纤维或颗粒状分布;挤压过程中发生动态再结晶,合金的抗拉强度(σb)由铸态的148.8 MPa提高到挤压态的210.2 MPa,伸长率(δ) 由铸态的2.8%提高到挤压态的19.9%;热挤压和热轧成形的Mg-2Nd合金,直接时效T5(extruded、rolled)处理能产生形变强化和时效硬化双重作用,其中T5(rolled)态合金σb高达276.4 MPa,δ较热轧态提高了64%;T5(rolled)态组织中出现了β'和β沉淀,尺度均在50 nm左右,对合金产生了明显的时效强化作用.
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