Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
李亚宁
,
董保胜
,
赵新伟
,
罗金恒
,
周根树
,
郑茂盛
钢铁研究
doi:10.3969/j.issn.1001-1447.2006.03.010
Q345是广泛使用的一种普通低合金钢,其断裂韧性是工程中进行裂纹检测的重要参数.应用J积分法测定了Q345的断裂韧性,并采用R6方法中的选择3曲线和通用曲线绘制了其失效评定曲线.研究发现:所有试样断口均有充分张开的大分层现象,它的存在阻碍了断口沿厚度方向的收缩,从而增加了材料的断裂韧性值.给出了适合Q345特性的失效评定曲线,以便为工程应用提供依据.
关键词:
Q345
,
J积分
,
断裂韧性
,
失效评估曲线
Physica B-Condensed Matter
Nanosize amorphous Fe-Ni-P-B alloy powders have been made by chemical reduction. The crystallization processes of the alloys have been studied by X-ray diffraction (XRD). The crystallization processes of different alloys vary with composition and chemical short-range order, which is determined by prepared conditions. A new kind of oxide phase (N-phase) has been found and determined by a double tilting method in transmission electron microscopy (TEM). This phase belongs to a body centered orthogonal lattice with a = 5.3 Angstrom, b = 8.5 Angstrom, c = 12.7 Angstrom.
关键词:
alloy particles;borohydride;tem
夏金魁
,
李相付
,
曹龙琼
,
黄道昌
,
陈敏明
连铸
doi:10.13228/j.boyuan.issn1005-4006.20150143
在降本增效的背景下,炼钢厂生产Q235B连铸板坯时,进行了成分优化和工艺流程简化,按照新工艺生产后,Q235B连铸板坯出现较多内部裂纹.经数据统计、低倍检验和扫描电镜分析后表明,Q235B连铸板坯产生内部裂纹主要是由钢水脱氧不良、夹杂物含量高,拉速和二次冷却控制不合理等原因造成,通过深脱氧、延长氩站软吹氩时间及降低浇铸速度等措施,新工艺在w[Mn]/w[S]≤30条件下,Q235B连铸板坯内部裂纹发生率降至原工艺水平.
关键词:
脱氧
,
吹氩
,
拉速
,
二次冷却
Philosophical Magazine a-Physics of Condensed Matter Structure Defects and Mechanical Properties
Complex structures can be regarded as bring derived from a few basic structures via the local twinning at the atomic level. Although quasicrystals and approximants are believed to be the B2 derivatives, the related B2 twinning mode is not known. This paper addresses this problem by analysing the twinning property of Al-Cu approximants in an Al3Cu4 sample. Such an analysis leads to the recognition of the B2 chemical-twinning mode as 180 degrees/[111]B-2, which is responsible for the pentagonal atomic configuration in the Al-Cu approximants as well as for the pseudofivefold B2 twinning observed on quasicrystal surfaces.
关键词:
quasi-crystals
Journal of Materials Processing Technology
The effects of concentrations or ratio of various reactants on the composition, particle size, morphology and crystalline structure of Fe-Ni-P-B nanoparticles fabricated by chemical reduction (CR) were systematically studied. The experimental results indicate that varying the ratio of Ni2+/(Ni2+ + Fe2+) can be used to control the ratio of Ni/(Ni + Fe) in the final products. It is also shown that the concentration of NaH2PO2 needs to be carefully controlled as any change will result in a large variation of composition in the final products. The reproducibility of CR for Fe-Ni-P-B system was also studied. It seems, from analyzing the experimental data, that two processes, namely chemical and electrochemical, were involved during the preparation. (C) 2001 Elsevier Science B.V. All rights reserved.
关键词:
nanoparticles;chemical reduction;amorphous;thermal-properties;alloy particles;powders;systems
梁浩
,
赵明久
,
陈胜虎
,
徐勇
,
王永利
,
戎利建
金属学报
doi:10.11900/0412.1961.2015.00255
采用OM,SEM,TEM,EPMA和二次离子质谱(SIMS)等手段,研究了B对J75抗氢合金晶界η相析出的抑制作用机制,采用饱和热充氢、三维原子探针(3DAP)技术和氢渗透实验方法,研究了B对合金抗氢性能的影响机制.结果表明,不含B合金中存在Ti的晶界偏聚,导致晶界7相在时效过程中析出;含B合金中,由于B抑制了Ti的晶界偏聚,使玎相难以形核长大,从而抑制了晶界η相的析出.B和H原子存在位置竞争关系,B降低合金的氢扩散系数,阻碍H原子的扩散和迁移,减少晶界偏聚H原子数量,抑制氢致裂纹形成.
关键词:
J75合金
,
B
,
抗氢性能
,
η相
