A high-strength magnesium alloy containing Yb was prepared through a simple hot extrusion process.The effect of Yb addition on dynamic precipitation,texture evolution,dynamic recrystallization mechanisms,deformation m...A high-strength magnesium alloy containing Yb was prepared through a simple hot extrusion process.The effect of Yb addition on dynamic precipitation,texture evolution,dynamic recrystallization mechanisms,deformation mechanisms,and strengthening mechanisms in as-extruded Mg-4 Sm-3 Gd(-2 Yb)-0.5 Zr(SGY0,SGY2)alloys was systematically investigated.The results indicated that the average grain size decreased from 4.17μm to 1.48μm with the addition of Yb.This extreme grain refinement greatly enhances the strength.The addition of Yb significantly facilitated the phase precipitation,but did not change the texture type.The non-dynamic recrystallized(un DRXed)grains exhibited a strong basal plane texture of<0110>parallel to the extrusion direction(ED),while the dynamic recrystallized(DRXed)grains showed a weaker rare earth texture,characterized by<1212>//ED.Moreover,the as-extruded SGY0 and SGY2 alloys predominantly undergo continuous dynamic recrystallization(CDRX),and some DRXed grains exhibit a discontinuous dynamic recrystallization mechanism(DDRX).In addition,the addition of Yb facilitates the activation of non-basal plane slip.The dislocation types in the as-extruded SGY0 and SGY2 alloys include(a),(c)and(c+a)dislocations.However,the SGY2 alloy exhibits a relatively high dislocation density,which contributes to the enhancement of the strength.Extreme grain refinement and the dispersion of nanoscale second-phase particles are key factors in increasing the strength.展开更多
本文从固相反应温度、晶转速率、生长速率及降温速率几个方面,探索分析了采用提拉法生长大尺寸Yb∶CALGO晶体的工艺。通过对比不同温度下烧结反应后的多晶料XRD图谱发现,原料在1350℃可以充分反应,根据所生长晶体的开裂截面形貌与晶体...本文从固相反应温度、晶转速率、生长速率及降温速率几个方面,探索分析了采用提拉法生长大尺寸Yb∶CALGO晶体的工艺。通过对比不同温度下烧结反应后的多晶料XRD图谱发现,原料在1350℃可以充分反应,根据所生长晶体的开裂截面形貌与晶体表面光滑度来优化晶转速率和生长速率,通过变温拉曼光谱分析降温速率导致开裂的成因,结合不同降温速率获得了不同方向的晶面应力分布图,发现对于沿着c轴生长的Yb∶CALGO晶体来说,降温速率过快更容易导致(001)面的热应力积累,这也是导致晶体在退火过程中开裂的主要诱因。采用多种手段优化晶体生长工艺后,实现了ϕ50 mm×110 mm Yb∶CALGO晶体的稳定生长,晶体具有较低的散射损耗(0.001796 cm^(-1))和较高的光学均匀性(4.21×10^(-5)),可以实现多种尺寸和形状的晶体元件加工,为进一步研制Yb∶CALGO板条激光器和超快激光器提供技术支撑。展开更多
文摘核因子(Nuclear Factor-Y,NF-Y)是一类能够在植物应对非生物胁迫过程中发挥转录调控作用的转录因子。为探究GmNF-YB2在大豆应对非生物胁迫过程中的功能和分子调控机制,本研究从大豆中克隆GmNF-YB2基因并对其进行生物信息学分析,采用实时荧光定量PCR(qRT-PCR)方法对GmNF-YB2的表达量进行检测,通过酵母双杂交方法分析GmNF-YB2蛋白与GmNF-YC6蛋白和GmNF-YC15蛋白的互作情况。结果显示:以大豆叶片cDNA为模板,PCR扩增获得678 bp GmNF-YB2基因序列。生物信息学分析结果显示,GmNF-YB2基因编码1个含有225个氨基酸的蛋白质,预测分子量为24.66 kD,等电点为6.97,是不稳定的亲水性蛋白质,定位于细胞核中;GmNF-YB2蛋白序列中含有一段保守的组蛋白折叠基序HFM。蛋白系统进化分析表明,GmNF-YB2与杨树PdNF-YB7和拟南芥AtNF-YB2的亲缘关系最近。qRT-PCR结果显示,GmNF-YB2在大豆幼苗中能够被干旱、盐和低温胁迫诱导表达,GmNF-YB2在大豆茎中的表达量最高。酵母双杂交结果显示,GmNF-YB2蛋白与GmNF-YC6蛋白和GmNF-YC15蛋白均存在互作关系。结果表明GmNF-YB2可能参与大豆对非生物胁迫的应答。
基金financially supported by the National Natural Science Foundation of China(No.52371108,52201119,52203295)Frontier Exploration Project of Longmen Laboratory,China(LMQYTSKT014)the Joint Fund of Henan Science and Technology R&D Plan of China(242103810056)。
文摘A high-strength magnesium alloy containing Yb was prepared through a simple hot extrusion process.The effect of Yb addition on dynamic precipitation,texture evolution,dynamic recrystallization mechanisms,deformation mechanisms,and strengthening mechanisms in as-extruded Mg-4 Sm-3 Gd(-2 Yb)-0.5 Zr(SGY0,SGY2)alloys was systematically investigated.The results indicated that the average grain size decreased from 4.17μm to 1.48μm with the addition of Yb.This extreme grain refinement greatly enhances the strength.The addition of Yb significantly facilitated the phase precipitation,but did not change the texture type.The non-dynamic recrystallized(un DRXed)grains exhibited a strong basal plane texture of<0110>parallel to the extrusion direction(ED),while the dynamic recrystallized(DRXed)grains showed a weaker rare earth texture,characterized by<1212>//ED.Moreover,the as-extruded SGY0 and SGY2 alloys predominantly undergo continuous dynamic recrystallization(CDRX),and some DRXed grains exhibit a discontinuous dynamic recrystallization mechanism(DDRX).In addition,the addition of Yb facilitates the activation of non-basal plane slip.The dislocation types in the as-extruded SGY0 and SGY2 alloys include(a),(c)and(c+a)dislocations.However,the SGY2 alloy exhibits a relatively high dislocation density,which contributes to the enhancement of the strength.Extreme grain refinement and the dispersion of nanoscale second-phase particles are key factors in increasing the strength.
文摘本文从固相反应温度、晶转速率、生长速率及降温速率几个方面,探索分析了采用提拉法生长大尺寸Yb∶CALGO晶体的工艺。通过对比不同温度下烧结反应后的多晶料XRD图谱发现,原料在1350℃可以充分反应,根据所生长晶体的开裂截面形貌与晶体表面光滑度来优化晶转速率和生长速率,通过变温拉曼光谱分析降温速率导致开裂的成因,结合不同降温速率获得了不同方向的晶面应力分布图,发现对于沿着c轴生长的Yb∶CALGO晶体来说,降温速率过快更容易导致(001)面的热应力积累,这也是导致晶体在退火过程中开裂的主要诱因。采用多种手段优化晶体生长工艺后,实现了ϕ50 mm×110 mm Yb∶CALGO晶体的稳定生长,晶体具有较低的散射损耗(0.001796 cm^(-1))和较高的光学均匀性(4.21×10^(-5)),可以实现多种尺寸和形状的晶体元件加工,为进一步研制Yb∶CALGO板条激光器和超快激光器提供技术支撑。
