力學(xué)性能的影響
(1.中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2.中國兵器科學(xué)研究院 寧波分院，寧波 315103)
摘 要: 利用光學(xué)顯微鏡、掃描電子顯微鏡、X射線衍射儀等研究二次擠壓對(duì)Mg-12Gd-3Y-0.6Zr合金顯微組織及力學(xué)性能的影響。研究表明：該合金經(jīng)二次擠壓后，晶粒尺寸細(xì)化至6 μm，提高細(xì)晶強(qiáng)化效果；粗大Mg5Gd1−xYx相增多，降低固溶強(qiáng)化效果；{0002}基面織構(gòu)的減弱降低織構(gòu)強(qiáng)化效果；在三者的綜合作用下，合金經(jīng)二次擠壓后，強(qiáng)度有所降低，但伸長率卻大幅度提高，達(dá)到20.5%，較一次擠壓態(tài)合金的伸長率提高107.1%；一次擠壓態(tài)合金的斷裂方式是以解理斷裂為主的混合斷裂，二次擠壓態(tài)合金的斷裂方式為韌性斷裂。
關(guān)鍵字: Mg-12Gd-3Y-0.6Zr合金；顯微組織；二次擠壓；力學(xué)性能；織構(gòu)
mechanical properties of Mg-12Gd-3Y-0.6Zr alloy
（1. School of Materials Science and Engineering, Central South University, Changsha 410083,China;
2. Ningbo Branch, Ordnance Science Institute of China, Ningbo 315103, China）
Abstract:The effect of double-extrusion on the microstructure and mechanical properties of Mg-12Gd-3Y-0.6Zr alloy was studied by optic microscopy (OM), scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The results show that, after double-extrusion, the grain size of this alloy is refined to 6 μm, which improves the strengthening effect of the fine grain. The coarse Mg5 Gd1−xYx phase increases, resulting in the decreases of solution strengthening effect. The weakening of {0002} basal plane texture decreases the strengthening effect of the texture. Under the comprehensive effect of the three factors, the strength of this alloy decreases slightly after double-extrusion, whereas the elongation increases remarkably to 20.5%, which is increased by 107.1% compared with that of the as-once-extruded alloy. The fracture mechanism of the as-once-extruded alloy is compound fracture cleavage fracture, and that of the as-double-extruded alloy is toughness and fracture.
Key words: Mg-12Gd-3Y-0.6Zr alloy; microstructure; double-extrusion; mechanical properties; texture
