Scanning Electron Acoustic Microscopy of GaInAsSb by Metalorganic Chemical Vapor Deposition

ＳｃａｎｎｉｎｇＥｌｅｃｔｒｏｎＡｃｏｕｓｔｉｃＭｉｃｒｏｓｃｏｐｙｏｆＧａＩｎＡｓＳｂｂｙＭｅｔａｌｏｒｇａｎｉｃＣｈｅｍｉｃａｌＶａｐｏｒＤｅｐｏｓｉｔｉｏｎＬｉＳｈｕｗｅｉ，ＪｉｎＹｉｘｉｎ，ＺｈｏｕＴｉａｎｍｉｎｇ，ＺｈａｎｇＢａｏｌｉｎ（李...     

Compositional Dependence of Surface Morphology and Electrical Properties of GaInAsSb Alloys Grown by Metalorganic Chemical Vapor Deposition

ＣｏｍｐｏｓｉｔｉｏｎａｌＤｅｐｅｎｄｅｎｃｅｏｆＳｕｒｆａｃｅＭｏｒｐｈｏｌｏｇｙａｎｄＥｌｅｃｔｒｉｃａｌＰｒｏｐｅｒｔｉｅｓｏｆＧａＩｎＡｓＳｂＡｌｏｙｓＧｒｏｗｎｂｙＭｅｔａｌｏｒｇａｎｉｃＣｈｅｍｉｃａｌＶａｐｏｒＤｅｐｏｓｉｔｉｏｎＮｉｎ...     

Prediction of Composition of GaInAsSb Epilayers by MOCVD Using Pattern Recognition and Artificial Neural Network Method

ＰｒｅｄｉｃｔｉｏｎｏｆＣｏｍｐｏｓｉｔｉｏｎｏｆＧａＩｎＡｓＳｂＥｐｉｌａｙｅｒｓｂｙＭＯＣＶＤＵｓｉｎｇＰａｔｅｒｎＲｅｃｏｇｎｉｔｉｏｎａｎｄＡｒｔｉｆｉｃｉａｌＮｅｕｒａｌＮｅｔｗｏｒｋＭｅｔｈｏｄＹａｎＬｉｕｍｉｎｇ①（严六明）ＥａｓｔＣｈ...     

分子动力学模拟不同层错能单晶Ni及其合金拉伸变形行为

采用分子动力学模拟了不同尺寸模型的单晶Ni及Ni₅₇Cr₁₉Co₁₉Al₅合金[100]晶向拉伸变形过程,确定了具有稳定塑性流变应力的模型尺寸,进一步研究了在具有稳定塑性流变应力的相同模型下单晶Ni及其合金拉伸变形行为。结果表明,层错能较低的单晶Ni₅₇Cr₁₉Co₁₉Al₅合金在小尺寸模型拉伸变形时,容易形成多层孪晶结构或变形孪晶;模型的横截面边长大于30倍的晶格常数时,塑性流变阶段流变应力、相结构及位错密度随应变起伏趋于平稳。具有稳定流变应力的相同尺寸单晶Ni及其合金拉伸时,层错能越低,塑性变形时层错面的面积越大。Shockley不全位错在单晶Ni及其合金塑性变形过程中起主导作用,多层孪晶的形成伴随着位错耗尽,变形孪晶的形成与湮灭则主要由位错饥饿机制主导。     

Texture and Microstructure Evolution During Tensile Testing of TWIP Steels with Diverse Stacking Fault Energy

Texture and microstructure evolution in two kinds of the twinning induced plasticity （TWIP） steels （Fe-Mn- Si-AI and Fe-Mn-C） with diverse stacking fault energies during tensile testing were investigated by interrupted testing. The strain-hardening rate curves of the two steels were quite similar, but the texture characterization curves （maximum of pole density measured by X-ray diffraction） were varied. According to the curvature of max pole density curves, the evolution of the texture and the microstructure can be divided into three stages： low strain stage, medium stage and high stage. In low strain stage the difference of the microstructure came from the intensity of dislocation, which was much smaller in Fe-Mn-Si-AI. The main difference of the microstructure in medium and high strain stages originated from the numbers of activated twin systems. There were more than one twin systems activated in Fe-Mn-C, while only a single twin system activated in Fe-Mn-Si-AI. Texture showed various differences in the whole tensile process because it was affected by their micromechanism, such as concentration of the dislocation and the activation of twin systems. Texture in low strain stage was connected with annealing twin; the evolution ofthe texture was mainly induced by deformation twin generation. More than one activated twin systems in medium and high stages may counteract each other in the view of concentration of the grain orientations.     

MOCVD Growth of Quaternary Ga_xIn_(1-x)As_(1-y)Sb_yAlloys:Solid Composition

ＭＯＣＶＤＧｒｏｗｔｈｏｆＱｕａｔｅｒｎａｒｙＧａｘＩｎ１－ｘＡｓ１－ｙＳｂｙＡｌｏｙｓ：ＳｏｌｉｄＣｏｍｐｏｓｉｔｉｏｎＺｈａｎｇＢａｏｌｉｎ，ＪｉｎＹｉｘｉｎ，ＺｈｏｕＴｉａｎｍｉｎｇ，ＮｉｎｇＹｏｎｇｑｉａｎｇ（张宝林）（金亿鑫）（周天明）（宁永强）ＪｉａｎｇＨｏｎｇａｎｄＬｉＳｈｕｗｅｉ（蒋红）（李树纬）ＣｈａｎｇｃｈｕｎＩｎｓｔｉｔｕｔｅｏｆＰｈｙｓｉｃｓ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｃｈａｎｇｃｈｕｎ，１３００２１，ＣｈｉｎａＲｅｃｅｉｖｅｄ２５Ｊｕｌｙ１９９…     

In situ neutron diffraction study of the microstructure and tensile deformation behavior in Al-added high manganese austenitic steels

In situ neutron diffraction experiments were performed to measure the tensile deformation behavior of high manganese austenitic steels with different Al contents (0, 1.5, 2.0, 3.0 wt.%). Significant variations of peak shift, broadening and asymmetry of the diffraction peaks were observed in the plastic region with the measurement. Diffraction peak profile analysis was applied to determine microstructural parameters such as stacking/twinning fault probabilities, dislocation density and stacking fault energy (SFE). These parameters are quantitatively correlated to the yield strength, serrated flow and strain hardening rate during tensile deformation. The main results showed that the twin/stacking fault probability considerably decreases from 0.05 to 0.01 and dislocation density from 10¹⁶ to 4 × 10¹⁵ m⁻² as a function of Al addition, while SFE (γ) increases from 20 to 45 mJ m⁻² with the relationship of γ = 8.84 wt.% Al + 19.0 mJ m⁻². Such microstructural parameters are also in good agreement with the results of the misorientation and pattern quality map obtained by the electron backscatter method.     

低辐射薄膜TiO2—Ag—TiO2—SiO的纳米尺度显微结构

成功地制务了TiO2-Ag-TiO2-SiO超薄多层膜的截面样品,并对其微观结构进行TEM,HREM及纳米束EDS分析,结果表明,薄膜各层厚度均匀,界面明锐、光滑。Ag层由纳米晶组成,而TiO2和SiO层为非晶。Ag在膜层中没有扩散或聚团,这也正是保证整个薄膜性能指标的一一个重要因素。     

Characterization of MLEC GaSb Crystal

ＣｈａｒａｃｔｅｒｉｚａｔｉｏｎｏｆＭＬＥＣＧａＳｂＣｒｙｓｔａｌ①ＴｕＨａｉｌｉｎｇ,ＤｅｎｇＺｈｉｊｉｅ②,ＺｈｅｎｇＡｎｓｈｅｎｇａｎｄＷｕＸｉｋａｎｇ（屠海令）（邓志杰）（郑安生）（武希康）ＧｅｎｅｒａｌＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｆｏ...     

Tailoring of misfit along interfaces between ZnxMn3−xO4 and Ag

This work is aimed at examining how the tetragonality of Zn_xMn_3−xO₄ spinel structures depends on the chemical composition when Zn_xMn_3−xO₄ is embedded in a metal matrix. The paper focuses on a wide range of Zn_xMn_3−xO₄ precipitates in a Ag matrix with x varying between 0 and 1.5. This variation of x has been obtained by internal oxidation of Ag–2at.%Mn–4at.%Zn in air followed by annealing in vacuo at different temperatures. It will be demonstrated that the Zn concentration x in Zn_xMn_3−xO₄ has a major influence on the interfacial misfit and orientation relation between Ag/Zn_xMn_3−xO₄. The degree of mismatch of 10.4% of 1 1 1 Ag–Mn₃O₄ and 2.4% of Ag–Zn_1.5Mn_1.5O₄ was visualized using the Bragg filtering technique on HRTEM micrographs of those interfaces. It was possible to identify misfit dislocations qualitatively with this technique at 1 1 1 Ag–Zn_xMn_3−xO₄ interfaces with different degree of mismatch.     

Fe-23Mn-0.6C TWIP钢的组织特征

研究了Fe-Mn-C系TWIP钢的微观组织特征。结果表明,钢板经热处理后,其室温组织为单相奥氏体基体并伴有退火孪晶,同时基体中存在退火孪晶和层错,其退火孪晶量达16.2%,由于锰含量较高在该系列钢中存在锰的偏析行为。     

高强度高塑性TWIP钢的组织和性能

研究了一种高强高塑的汽车用TWIP钢。TWIP钢的锰含量为15％～30％,抗拉强度为600～1100MPa,断后伸长率高达95％。介绍了孪晶诱发相变的微观机理,层错能对TWIP效应的影响以及显微组织对钢的力学性能的影响。锰含量为15％～30％时,钢的塑性得以提高的机理主要是γ→ε→α相变诱发的TRIP效应;随着锰含量增加,孪晶形成逐渐起主导作用。     

Slip transmission across fcc/bcc interfaces with varying interface shear strengths

Interfaces with relatively low shear strengths can be strong barriers to slip transmission because of core spreading of the dislocation within the interface. Using atomistic modeling and elasticity-based calculations we have studied the influence of interface shear strength on the slip transmission of a single dislocation across fcc/bcc interfaces. “Tunable” interatomic potentials were employed to vary the interface shear strength for the same interface crystallography. The results show that the slip transmission barrier increases with decreasing shear strength of the interface. The results reveal a mechanism for the variations in ultra-high strengths observed in nanoscale fcc/bcc multilayers.