王群
,
王文忠
,
高钦
,
沈玉辉
,
陈建峰
无机材料学报
本文分析了以Lanxide技术合成AlN的生长过程，发现AlN晶体生长具有明显的方向性，XRD分析表明：AlN晶体的生长方向为[0001]晶向.反应过程中AlN由基体表面向气氛中不断深入生长，形成了纤维状或称柱状晶体组织.反应初期Mg元素的挥发非常强烈，Mg蒸气参与表面反应，生成一层疏松的复相表层，有利于反应的深入进行.氮化过程中Si元素存在富集现象，造成宏观组织的成份不均匀性.
关键词:
反应
,
alloy
,
reaction
,
growth
任英
,
张立峰
,
李燕龙
,
余乐
,
李刚
,
李军涛
钢铁研究学报
运用商业软件Ansys-Fluent,建立了1t钢包底吹氩与合金熔化扩散数值模型,其中钢包吹氩模型通过Wood'sMetal物理试验验证,吻合很好.研究采用数值模拟与现场试验相结合的方法分析了钢包内流场与合金加入的位置及方式对合金在钢包内扩散的影响.结果表明:260L/min吹氩流量过大,且吹氩时间过长(120s),建议使用100 L/min的吹氩流量,加合金前吹氩时间30s,使Al块熔化与混均,保护合金,加合金后吹氩30s,降低合金的烧损.合金采用加入棒固定,在吹氩口上方加入后保持3～5 s,熔化时间能由6.2s降低至2.0s,混匀时间能由35s降低至23s.另外,在降低烧损的同时,减少吹氩量和温降,起到节能减排的作用.
关键词:
钢包
,
底吹氩
,
合金
,
混匀时间
,
数值模拟
F. Gesmundo
,
Y Niu
,
F. Vianiand D.L. Douglass(Universita di Genova
,
Fiera del Mare
,
Pad. D
,
16129 Genova
,
Italy)(State Key Lab. for Corrosion and Protection
,
Institute of Corrosion and Protection of Metals
,
theChinese Academy of Sciences
,
Shenyang 110015
,
China)(University of Arizona
,
4715 East Fort Lowell Road
,
TUcson
,
AZ 85712
,
USA)
金属学报(英文版)
The cormsion in air of a two-phase Cu-75Cr alloy was studied at 700-900℃. Thealloy cormded nearly parabolically at 700-800℃, but at 900℃ its instantaneousparabolic mte constant decreased with time. The scales were complex and consistedof an outermost layer of copper oxide generally followed bg a layer of the double ox-ide Cu2 Cr2 O4 sometimes containing particles of unoxidized chromium surmunded bya chromia layer. An innermost layer of chromia was also observed in some cases.Finally metallic copper was al8o frequently mixed with chromia particles. No Cr de-pletion was observed in the alloy close to the inteffoce with the scale. In any case,this alloy was not able to form an exclusive continuous protective chromia layer. Thespecial cormsion behavior Of this alloy is typical of two-phase binary systems with alange solubility gaP in which the outwaof dthesion fiux of the most-reactive componentin the alloy is strongly reduced and may be inswncient to fOrm a protective externallayer of the cormsponding oxide. In paTticular, the presence of particles of Cr withina double oxide layer is very unusual and is allowed only for the kinetic reason.
关键词:
copper-chromium
,
null
,
null
,
null
Z.F.Peng1)
,
Y.Y.Ren1)
,
Q.S. Mei1)
,
Y.Q.Wang2)
,
X.Y.Zhang2) and M.S.Ye2) 1) Department of Materials Engineering
,
Wuhan University of Hydraulic and Electric Engineering
,
Wuhan430072
,
China 2) Department of Superalloys
,
CentralIron and Steel Research Institute
,
Beijing430072
,
100081 China
金属学报(英文版)
Theeffectsof Nband Ti+ Nb microalloyingon mechanicalpropertiesand rupturelifeunder900 ℃ tensiletest on alloy GH652 were studied. Among theoriginalalloy GH652 and its Nb/ Ti+ Nb microalloyed alloys, the Ti+ Nb microalloyed alloy exhibited optimum com bined900℃ tensilestrength and plasticity and longer 900℃ 49 MPa prolonged tensile rup turelife as well. The role of refractory alloying elementscould be effectively brought intoplay with highertemperaturesolution treatment. Coordination strengthening of Matrix andgrain boundary wasthekeyfactoroflifetimeextension andthe mobilityof dislocationsinthematrix wasresponsableforthe plasticity ofthe micro alloyedsamples.
关键词:
GH652 Nb/ Ti+ Nb micro alloying
,
null
,
null
,
null
