近年来,自旋电子学的发展与应用已经使科研工作者在计算机存储等领域的研究取得极大进展。采用基于密度泛函理论的第一性原理方法,运用美国Materials Studio 6.0 CASTEP软件计算金属化合物Mn4N的性质。首先,从量子力学的角度考虑电子的...近年来,自旋电子学的发展与应用已经使科研工作者在计算机存储等领域的研究取得极大进展。采用基于密度泛函理论的第一性原理方法,运用美国Materials Studio 6.0 CASTEP软件计算金属化合物Mn4N的性质。首先,从量子力学的角度考虑电子的电荷特性和自旋特性,建立Mn4N的结构模型,计算最优化晶格常数、能带结构和态密度,确定其体模量、剪切模量、杨氏模量和泊松比,计算得到最优化晶格常数为3.838。其次,在几何优化的基础上,计算Mn4N的磁性性质,总磁矩为-0.82μB,说明其为良好的亚铁磁性金属材料,磁性主要来源于Mn1原子和Mn2原子d电子的自旋及其在费米能级附近劈裂和相互杂化。展开更多
采用不同腐蚀剂对热轧态和时效态5Cr21Mn9Ni4N耐热钢进行腐蚀,研究了不同腐蚀剂对5Cr21Mn9Ni4N钢腐蚀效果的影响。结果表明:传统的硝酸乙醇溶液无法腐蚀试样,试样表面无任何变化;三氯化铁盐酸水溶液无法使试样显示清晰完整的组织及晶界...采用不同腐蚀剂对热轧态和时效态5Cr21Mn9Ni4N耐热钢进行腐蚀,研究了不同腐蚀剂对5Cr21Mn9Ni4N钢腐蚀效果的影响。结果表明:传统的硝酸乙醇溶液无法腐蚀试样,试样表面无任何变化;三氯化铁盐酸水溶液无法使试样显示清晰完整的组织及晶界,且存在过度腐蚀现象;采用5 g FeCl_(3)+50 mL HCl+100 mL H_(2)O腐蚀剂与10 g CuSO_(4)+15 mL H_(2)SO_(4)+100 mL HCl+5 mL C_(3)H_(8)O_(3)腐蚀剂配合使用,在室温下对热轧态及时效态5Cr21Mn9Ni4N钢进行腐蚀,能够清晰显示材料的奥氏体组织。展开更多
The microstructure, composition and shape of precipitated phase under as-cast and finished product state of 5Cr21Mn9Ni4N steel with different rare earth （RE） amount were studied. Mechanical properties of 5Cr21Mn9Ni4...The microstructure, composition and shape of precipitated phase under as-cast and finished product state of 5Cr21Mn9Ni4N steel with different rare earth （RE） amount were studied. Mechanical properties of 5Cr21Mn9Ni4N steels withont RE addition and with RE added by 0. 2% in mass percent were tested respectively. The results indicate that the solid solution amount of RE is about 10^-6 -10^-5 order of magnitude in 5Cr21Mn9Ni4N steel. Dendrite of as-cast condition is refined obviously and dimension of interstitial phase is shortened when RE is added by 0.10%-0.20%. But the microstructure will be coarser if surplus RE is added. Precipitated phase under finished product state distributes evenly in nearly same size with RE added by 0. 2% which leads to a largely improved high temperature mechanical property.展开更多
The oxidation resistance of 5Cr21Mn9Ni4N steel micro-alloying by RE at 700 - 900 ℃ was investigated. The results indicate that oxidation exponent n and oxidation activation energy are increased, and oxidation velocit...The oxidation resistance of 5Cr21Mn9Ni4N steel micro-alloying by RE at 700 - 900 ℃ was investigated. The results indicate that oxidation exponent n and oxidation activation energy are increased, and oxidation velocity constant kp is decreased when 0.2% RE is added in 5Cr21Mn9Ni4N steel. The addition of RE elements does not alter phase constitution of oxidation scale, however it improves the configuration of oxidation scale, and increases thermal stability and adhesivity of oxidation scale, which results in the raise of oxidation resistance of 5Cr21Mn9Ni4N steel at high temperature. The oxidation scale constitutes of refractory steel transfer from manganic oxide mostly to ferric oxide mostly with the increase of temperature, which leads to descend of compactness and desquamation resistance of oxidation scale. The mass increase of ferric oxide in the oxidation scale and the looseness of oxidation scale are the main reason to descend the oxidation resistance of refractory steel.展开更多
The influence of different rare earth amounts on microstructure and mechanical properties of 5Cr21Mn9Ni4N steel was studied. The microstructure and composition and shape of inclusions under as-cast, as well as hot rol...The influence of different rare earth amounts on microstructure and mechanical properties of 5Cr21Mn9Ni4N steel was studied. The microstructure and composition and shape of inclusions under as-cast, as well as hot rolling state of 5Cr21Mn9Ni4N steel were observed under metallographic microscope and SEM. The results indicate that dendrite of as-cast condition is refined obviously, the extent of segregation is lightened, dimension of inclusions is lessened, and the shape of inclusions is changed from polygon to ellipse when appropriate amount of mixed rare earth is added. Appropriate rare earth also can lighten the extent of hot rolling texture and improve distribution of carbide under hot rolling state. The results of room temperature and 500 ℃ tensile test show that room temperature tensile strength is firstly improved and then appreciably descended. The elongation percentage decreased with the increase of rare earth amount. Appropriate rare earth amount can improve the high temperature tensile strength and ductility of 5Cr21Mn9Ni4N. Fracture surface observation and energy spectrum analysis indicate that complicated rare earth inclusions appear in the fracture surface when 0.10% (mass fraction) rare earth is added in experimental steels, and tough nests of fracture surface become fine without big hole.展开更多
文摘近年来,自旋电子学的发展与应用已经使科研工作者在计算机存储等领域的研究取得极大进展。采用基于密度泛函理论的第一性原理方法,运用美国Materials Studio 6.0 CASTEP软件计算金属化合物Mn4N的性质。首先,从量子力学的角度考虑电子的电荷特性和自旋特性,建立Mn4N的结构模型,计算最优化晶格常数、能带结构和态密度,确定其体模量、剪切模量、杨氏模量和泊松比,计算得到最优化晶格常数为3.838。其次,在几何优化的基础上,计算Mn4N的磁性性质,总磁矩为-0.82μB,说明其为良好的亚铁磁性金属材料,磁性主要来源于Mn1原子和Mn2原子d电子的自旋及其在费米能级附近劈裂和相互杂化。
文摘采用不同腐蚀剂对热轧态和时效态5Cr21Mn9Ni4N耐热钢进行腐蚀,研究了不同腐蚀剂对5Cr21Mn9Ni4N钢腐蚀效果的影响。结果表明:传统的硝酸乙醇溶液无法腐蚀试样,试样表面无任何变化;三氯化铁盐酸水溶液无法使试样显示清晰完整的组织及晶界,且存在过度腐蚀现象;采用5 g FeCl_(3)+50 mL HCl+100 mL H_(2)O腐蚀剂与10 g CuSO_(4)+15 mL H_(2)SO_(4)+100 mL HCl+5 mL C_(3)H_(8)O_(3)腐蚀剂配合使用,在室温下对热轧态及时效态5Cr21Mn9Ni4N钢进行腐蚀,能够清晰显示材料的奥氏体组织。
文摘The microstructure, composition and shape of precipitated phase under as-cast and finished product state of 5Cr21Mn9Ni4N steel with different rare earth （RE） amount were studied. Mechanical properties of 5Cr21Mn9Ni4N steels withont RE addition and with RE added by 0. 2% in mass percent were tested respectively. The results indicate that the solid solution amount of RE is about 10^-6 -10^-5 order of magnitude in 5Cr21Mn9Ni4N steel. Dendrite of as-cast condition is refined obviously and dimension of interstitial phase is shortened when RE is added by 0.10%-0.20%. But the microstructure will be coarser if surplus RE is added. Precipitated phase under finished product state distributes evenly in nearly same size with RE added by 0. 2% which leads to a largely improved high temperature mechanical property.
文摘The oxidation resistance of 5Cr21Mn9Ni4N steel micro-alloying by RE at 700 - 900 ℃ was investigated. The results indicate that oxidation exponent n and oxidation activation energy are increased, and oxidation velocity constant kp is decreased when 0.2% RE is added in 5Cr21Mn9Ni4N steel. The addition of RE elements does not alter phase constitution of oxidation scale, however it improves the configuration of oxidation scale, and increases thermal stability and adhesivity of oxidation scale, which results in the raise of oxidation resistance of 5Cr21Mn9Ni4N steel at high temperature. The oxidation scale constitutes of refractory steel transfer from manganic oxide mostly to ferric oxide mostly with the increase of temperature, which leads to descend of compactness and desquamation resistance of oxidation scale. The mass increase of ferric oxide in the oxidation scale and the looseness of oxidation scale are the main reason to descend the oxidation resistance of refractory steel.
文摘The influence of different rare earth amounts on microstructure and mechanical properties of 5Cr21Mn9Ni4N steel was studied. The microstructure and composition and shape of inclusions under as-cast, as well as hot rolling state of 5Cr21Mn9Ni4N steel were observed under metallographic microscope and SEM. The results indicate that dendrite of as-cast condition is refined obviously, the extent of segregation is lightened, dimension of inclusions is lessened, and the shape of inclusions is changed from polygon to ellipse when appropriate amount of mixed rare earth is added. Appropriate rare earth also can lighten the extent of hot rolling texture and improve distribution of carbide under hot rolling state. The results of room temperature and 500 ℃ tensile test show that room temperature tensile strength is firstly improved and then appreciably descended. The elongation percentage decreased with the increase of rare earth amount. Appropriate rare earth amount can improve the high temperature tensile strength and ductility of 5Cr21Mn9Ni4N. Fracture surface observation and energy spectrum analysis indicate that complicated rare earth inclusions appear in the fracture surface when 0.10% (mass fraction) rare earth is added in experimental steels, and tough nests of fracture surface become fine without big hole.
