张康侯
贵金属
doi:10.3969/j.issn.1004-0676.2008.02.011
评述了1996～2007年国际上对含金三元合金系相图、相变的研究进展.1996年以来,在主要国际专业刊物上发表了30多个三元金合金系相图的部分等温截面或纵截面,采用实验方法研究相图的工作占了绝大部分.在所研究的上述三元金合金系中,Au-Sn基合金系有11个,Au-Ag基合金系有6个,Au-Cu和Au-Sb基合金系各有4个,Au-Mn和Au-Si基合金系各有2个.这些合金系目前涉及到的主要应用领域为:钎焊材料、电触头材料、电子材料、磁性材料、形状记忆合金材料、金属离子源材料和喷丝头材料等.含金三元合金系的研究反映了当前对新型金合金功能材料的需求动向, 对指导促进相关新合金材料的开发有重要意义.
关键词:
金属材料
,
金合金
,
三元合金系
,
相图
,
进展
Rong MA
金属学报(英文版)
Two heats of low activation martensitic (LAM) steels with Ti and Ta (denominated as 9Cr-Ti and 9Cr-Ta), respectively, developed as candidate structure materials for nuclear reactor were characterized. This paper was focused on the effect of titanium on the microstructures and mechanical properties of 9Cr LAM steel in as-received condition (normalized at 950℃ for 30 min with water quenching plus tempered at 780℃ for 90 min with air cooling). Chemical analysis and microstructure observation were conducted on 9Cr-Ti and 9Cr-Ta with optical microscopy, X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. Impact properties and tensile strengths were measured with Charpy impact experiments and tensile tests. The results indicated that 9Cr-Ti and 9Cr-Ta were fully martensitic steels in as-received condition. MX type and M23C6 type precipitates were observed distributing along boundaries of prior austenite grains and martensite laths in 9Cr-Ti. The addition of titanium accelerated the precipitation of TiC and TiN, and produced much finer grains in 9Cr-Ti than 9Cr-Ta at the same normalization temperature. Mechanical properties tests showed the ductile brittle transition temperatures of 9Cr-Ti and 9Cr-Ta were about -90℃ and -85℃, respectively. The ultimate tensile strengths at room temperature and 600℃ were 680 MPa and 365 MPa for 9Cr-Ti, and 660 MPa and 335 MPa for 9Cr-Ta, respectively. The favorite impact toughness and tensile properties of 9Cr-Ti could be attributed to the fine grains in as-received condition.
关键词:
9Cr low activation martensitic steel
Applied Physics Letters
A complicated behavior was indicated in nanocrystalline Fe78Si9B13 alloy with grain size lower than 65 nm. No sign of dislocations after deformation has been found in nanocrystalline material, suggesting that it is unlikely that the dislocation pileup is involved. The reduction of the mean hyperfine field is attributed to a decrease in the number of nearest neighbor atoms on the grain boundaries, which may be responsible for the softening behavior in nanocrystalline material with an average crystallite size of 65 nm. An increasing peak of the phonon mode near 900 cm(-1), reflecting strong electron-atom coupling in grain boundary of nanocrystalline material, was observed. (C) 1996 American Institute of Physics.
关键词:
Applied Physics Letters
A preferential precipitation sequence of metastable phase formation during crystallization of an amorphous alloy (Fe0.99Mo0.01)(78)Si9B13 was revealed as following: alpha-Fe(Si, Mo) (bcc) --> (Fe,Mo)(3)B (BCT), (Fe,Mo)(3.0)B (BCT), and (Fe,Mo)(23)B-6 (fcc) --> Fe2B. An ordering process of atom cluster occurs prior to the crystallization. Above experimental sequence of crystallization of (Fe0.99Mo0.01)(78)Si9B13 metallic glass could be understood in terms of the Gaskell model, There is a high strain (0.33%) in the alpha-Fe(Si, Mo) (bcc) grain with 37 nm, and the strain relaxation leads to the distortion in the lattice parameter of nanocrystallite. (C) 1996 American Institute of Physics.
关键词:
屈凤波
,
杨振强
,
樊燕鸽
,
陈辉
,
杨瑞娜
合成材料老化与应用
以溴苯为起始原料,经过格氏反应,偶联反应,加成反应,酸催化闭环合成了2-溴-9,9'-螺二芴,最后与二苯基膦锂锂化反应合成目标化合物二苯基-2-(9,9'-螺二芴基)膦,总收率为60.6％.通过1H NMR确证了目标化合物的结构.
关键词:
二苯基-2-(9,9'-螺二芴基)膦
,
2-溴-9,9'-螺二芴
,
合成与表征
