材料期刊网

MSSBAUER INVESTIGATION ON QUENCHED STRUCTURES OF 40CrNiMo STEEL

XU Zuxiong MA Ruzhang ZHU Yongquan ZHAO Zhongtao FENG Yongrong Beijing University of Science and Technology , Beijing , China [Originally published in ACTA METAIL SIN (CHINESE EDN) 24 (5) 1988 pp B364—B368 , received 24 January 1987 , in revised form 27 November 1987]

金属学报(英文版)

The martensite microstructure,amount of retained austenite and its carbon concentration in the 40CrNiMo steel quenched at various conditions have been investigated by using trans- mission Mossbauer spectroscopy at room temperature.It was shown that high-temperature quenching and thermomechanical quenching has little influence on amount of retained austenite,thus the toughening effect of quenching was attributed to bulk lath martensite and its refining.

关键词: 40CrNiMo steel , null , null

EFFECT OF HYDROGENATION ON THE MICROSTRRUCTURE OFTi-24Al-14Nb-3V-0.5Mo ALLOY

L. Dong , L.G. Zhou , H. Ding and C.B. Zhang(Laboratory of Atomic Imaging of Solids , Institute of Metal Research , The Chinese Academy of Sciences , Shenyang 110015 , China)(Departmeot of Material Science , Northeastern University , Shenyang 110006 , China)

金属学报(英文版)

The ebct of hydrogenation-dehydrogenation on the microstructure of forping Ti-24Al14Nb-3V-0.5MO alloy was investigated by TEM and X-ray ddection. The resultsshowed that the microstructure consists of O and B2 phases as received materials, and tmoprmation of B2 phase to O phase can be eNctively promoted 6y hydrogenation. The lamellate γ hydride was found in O phase with more hydmpen content, and this γ hydride could be decomposed by dehydmpenation treatment. The sole fine Ophase could be obtained 6y hydmpenation-dehydmpenation treatment, and two possible mechanisms for the microstructure improvetnent have been discussed on the basis of experimental results.

关键词: Ti_3Al-based alloy , null , null

En24钢在海水中的应力腐蚀

王正

中国腐蚀与防护学报

用恒位移弯曲试验,慢应变速率试验、动电位扫描和浸蚀试验研究了En24钢在海水中的应力腐蚀特性。结果表明,En24钢的环境敏感断裂倾向随强度降低而降低;强度低于临界值,则不出现应力腐蚀裂缝。外加电位对En24钢的环境敏感特性有重要影响,裂缝扩展平台速度于-900mV处出现极小值。依据裂缝扩展动力学、断口形貌、物理冶金参数和电化学等方面的判据,认为En24钢在海水中的应力腐蚀与电位密切相关。低于-900mV,属氢致开裂;高于-900mV,则由阳极溶解过程所制约;在一定电位范围内,不排除两种机理共同作用的可能性。

关键词:

Ni52MI24Ga24金属间化合物的单晶生长和磁性功能

陈京兰 , 胡凤霞 , 高书侠 , 王中 , 高智勇 , 赵连城 , 宫声凯 , 徐惠彬

金属学报

研究了Ni52Mn24Ga24合金单晶在磁场作用下能产生的目前最大的磁致伸缩应变.发现了该材料的双向相变应变效应以及磁场对此的增强现象在1.2 T磁场的作用下,可逆的相变应变达4%以上.实现这一结果的关键条件是马氏体变体的择优取向报道了获得马氏体变体的择优取向样品的单晶生长特性和后处理方法.根据前人报道的理论模型分析了实验结果,指出磁感生应变的物理机制是磁场提供的Zeeman能驱动变体间孪晶界的移动.

关键词: Ni52Mn24Ga24 , null , null

Ni52MI24Ga24金属间化合物的单晶生长和磁性功能

陈京兰 , 胡凤霞 , 高书侠 , 王中 , 高智勇 , 赵连城 , 宫声凯 , 徐惠彬

金属学报 doi:10.3321/j.issn:0412-1961.2001.04.004

研究了Ni52Mn24Ga24合金单晶在磁场作用下能产生的目前最大的磁致伸缩应变.发现了该材料的双向相变应变效应以及磁场对此的增强现象在1.2 T磁场的作用下,可逆的相变应变达4%以上.实现这一结果的关键条件是马氏体变体的择优取向报道了获得马氏体变体的择优取向样品的单晶生长特性和后处理方法.根据前人报道的理论模型分析了实验结果,指出磁感生应变的物理机制是磁场提供的Zeeman能驱动变体间孪晶界的移动.

关键词: Ni52Mn24Ga24 , 形状记忆 , 磁致伸缩

Ti-24A1-17 Nb合金的激光焊接

吴爱萍 , 邹贵生 , 张红军 , 王国庆 , 谢美蓉

宇航材料工艺 doi:10.3969/j.issn.1007-2330.2001.06.016

研究了Ti-24Al-17Nb合金的激光焊接及其接头的力学性能.研究结果表明,连续激光氦气双面保护可以获得保护效果可靠、无缺陷、成型良好的焊接接头.焊接热输入增大不利于接头的纵向弯曲塑性,而接头的横向拉伸强度与母材基本相同,塑性可以接近母材的塑性,达到14%～17%.

关键词: Ti3Al基合金 , 激光焊接 , 接头性能

THERMODYNAMICS OF BAINITIC TRANSFORMATION IN Cu-24 at.-% Al ALLOY

XU Zuyao (T.Y.Hsu) ZHOU Xiaowang Shanghai Jiaotong University , China Professor , Department of Materials Science , Shanghai Jiaotong University , Shanghai 200030 , China

金属学报(英文版)

Two driving forces △G~((β_1)+α')and △G~(β_1→β_2+α)for the bainitic transformation have been calcu- lated for Cu-24 at.-% Al alloy.Results reveal △G~(β_1→α')>0 within the transformation tem- perature range 600—750 K.Therefore,the bainitic transformation cannot be initiated by the β_1→α' shearing mechanism.On the other hand,the driving force △G~(β_1→β_2+α)to produce 5% of the α becomes negative only when the composition of the α satisfies x_(Al)~α≤0.204 at 700 K or x_(Al)~α=0.209 at 750 K.So the bainitic transformation can only proceed by β_1→β_2+α diffusional reaction with different diffusion amount at different temperatures.

关键词: Cu-Al alloy , null , null

Ti-24Al-15Nb-1Mo合金氩弧焊

刘卫红 , 李艳 , 毛唯 , 李晓红 , 曹春晓

航空材料学报 doi:10.3969/j.issn.1005-5053.2006.03.023

研究用Ti-Al-Nb基(高Nb)合金作填充材料氩弧焊(充氩箱中)Ti-24Al-15Nb-1Mo合金时的焊缝成形及其接头显微结构和力学性能特点.结果表明,固溶处理状态下母材氩弧焊时具有较低的冷裂纹敏感性.焊态下,接头抗拉强度912～927MPa,延伸率2.5%～3.7%,焊缝冲击韧性4.7J/cm2～10.4J/cm2,近热影响区是接头力学性能的薄弱区域.

关键词: Ti3Al基合金 , 氩弧焊 , 显微结构 , 力学性能

单晶Ni52Mn24Ga24的磁感生应变和磁增强双向形状记忆效应

柳祝红 , 王文洪 , 陈京兰 , 高淑侠 , 吴光恒

金属功能材料 doi:10.3969/j.issn.1005-8192.2001.02.007

铁磁性Heusler合金Ni2MnGa是近年开发的磁控制功能材料,已发现该材料结合马氏体相变可以产生大磁致伸缩(磁感生应变)和磁控制形状记忆效应两种应用功能.用磁悬浮冷坩埚提拉设备沿[001]方向生长了组分为Ni52Mn24Ga24的单晶.室温时沿该单晶样品[001]方向加磁场,在该方向获得了-0.6%的大磁感生应变.当磁场方向垂直于[001]方向时,样品在[001]方向的磁感生应变值为0.5%.同时该单晶样品在室温附近还具有可由磁场增强和控制的双向形状记忆效应.无磁场作用时,降低温度,样品在发生马氏体相变时,在[001]方向产生1.2%的收缩形变.随后升高温度,反马氏体相变时样品以同样的应变量膨胀,恢复到原来的形状,显示了特有的无需外应力协助的自发的双向形状记忆效应.其温度滞后只有10℃.如果在样品的[001]方向加一个偏磁场,其形状记忆的应变量随磁场的增强而增大.在磁场为1.2T时可达4%.而当磁场转向[100]方向时,形状记忆的应变可以改变符号.本文指出产生大磁感生应变和磁增强双向形状记忆效应的关键是马氏体变体的择优取向.

关键词: 磁感生应变 , 双向形状记忆效应 , Ni52Mn24Ga24

(14-x)SrCO3-xCaCO(3)-24CuO system to synthesize spin-ladder compounds Sr14-xCaxCu24O41 using DTA and XRD techniques

Chinese Journal of Chemical Physics

The (14 - x) SrCO3-xCaCO(3)-24CuO system was investigated by means of differential thermal analysis (DTA) technique combined with the powder X-ray diffraction (XRD) technique, and the relationship of its thermal behavior with the synthesis of spin-ladder compound Sr14-xCaxCu24O41 was first analyzed in detail. It is found that the DTA curve (x <= 5.6) exhibits two endothermic peaks and could be divided into three reaction stages, corresponding to the solid state reaction to synthesize single-phase Sr14-xCaxCu24O41. The DTA curve (x >= 8.4) shows three big endothermic peaks below 1000 degrees C. The intensity and the position of the first endothermic peak around 800 degrees C is depending on the content of CaCO3 in the system, while the third endothermic peak is the crucial factor of the synthesis of single-phase compound.

关键词: solid state reaction;powder X-ray diffraction;differential thermal;analysis;phase transformation;sro-cao-cuo;phase-relationships