关于Fe－28Al合金中的析出相

用磁性分析、显微组织观察和Ｘ射线衍射对淬火态Ｆｅ—２８Ａｌ合金的结构进行了研究．结果表明，合金从Ｂ２区淬火后沿晶粒边界可有第二相析出，已初步确定它是Ｆｅ和Ａｌ的碳化物Ｆｅ_３ＡｌＣ_ｘ（ｋ相）．     

Fe_3Al系合金环境氢脆研究SCIEI

研究了晶粒尺寸、形状、应变速率及预氧化对Ｆｅ_３Ａｌ系合金环境氢脆的影响，结果表明，细化晶粒能显著提高Ｆｅ_３Ａｌ合金在纯氧中的塑性及强度，但不能根本改善其环境氢脆敏感性；随着应变速率的提高，Ｆｅ_３Ａｌ合金在空气中的延伸率增加；Ｆｅ_３Ａｌ在空气及氢气中的脆化程度相似；预氧化能部分消除Ｆｅ_３（Ａｌ，Ｃｒ，Ｂ）合金的环境氢脆。实验结果可用表面化学反应是Ｆｅ_３Ａｌ材料环境致脆的控制步骤这一假设予以解释．     

快速凝固Al—8.3Fe—1.9V—2.1Si合金的相转变

借助扫描电子显微分析、Ｘ射线衍射技术、差热分析手段研究了快速凝固Ａｌ－８．３Ｆｅ－１．９Ｖ－２．１Ｓｉ合金的相组成及相转变温度。结果表明，合金中的相组成为αＡｌ＋Ａｌ１３（Ｆｅ，Ｖ）３Ｓｉ相；在６３８℃－６４５℃温度范围内，立方结构的Ａｌ１３（Ｆｅ，Ｖ）３Ｓｉ相向六方结构的Ａｌ３（Ｆｅ，Ｖ，Ｓｉ）相转变。钒添加至Ａｌ－Ｆｅ－Ｓｉ合金中，提高了快速凝固Ａｌ－８．３Ｆｅ－１．９Ｖ－２．１Ｓｉ合金粉末的     

INHIBITORY ACTION OF Si ON GROWTH OF INTERFACIAL COMPOUND LAYER DURING HOT－DIP ALUMINIZING

对添加２ａｔ．－％Ｓｉ后热浸镀Ａｌ钢带界面化合物层的结构和组成进行了实验研究。结果发现，Ｓｉ在界面化合物层区产生富集，界面化合物具有Ｆｅ_２Ａｌ_５相的结构，其化学式可写成Ｆｅ_２（ＡｌＳｉ）_５．认为Ｓｉ的作用在于填充Ｆｅ_２Ａｌ_５相中的原子空位，阻碍Ａｌ的扩散，使界面化合物层厚度大大下降．     

快速凝固Al－Fe－Ti－C合金的显微结构及退火过程中的相变SCIEI

研究了快速凝固Ａｌ－Ｆｅ－Ｔｉ－Ｃ合金的显微结构及退火过程中的相变。初始快凝态组织由α－Ａｌ微胞晶组成，在胞晶边界分布着较大并拉长的非晶相；在胞晶内部则为细小弥散的球状亚稳Ａｌ_６Ｒｅ相（底心正交结构），Ｔｉ和Ｃ全部过饱和固溶于α－Ａｌ中。当７７３Ｋ退火５ｈ时，非晶相转变为α_Ｔ－ＡｌＦｅＳｉ相（斜方结构），Ａｌ_６Ｆｅ相部分转变为片状Ａｌ_３Ｆｅ相（底心单斜结构），部分长大但仍保持球状和底心正方结构过饱和固溶于α－Ａｌ基体中的Ｔｉ和Ｃ则以ＴｉＣ形式弥散析出。     

快速凝固Al－Fe－Ti－C合金的显微结构及退火过程中的相变

研究了快速凝固Ａｌ－Ｆｅ－Ｔｉ－Ｃ合金的显微结构及退火过程中的相变。初始快凝态组织由α－Ａｌ微胞晶组成，在胞晶边界分布着较大并拉长的非晶相；在胞晶内部则为细小弥散的球状亚稳Ａｌ_６Ｒｅ相（底心正交结构），Ｔｉ和Ｃ全部过饱和固溶于α－Ａｌ中。当７７３Ｋ退火５ｈ时，非晶相转变为α_Ｔ－ＡｌＦｅＳｉ相（斜方结构），Ａｌ_６Ｆｅ相部分转变为片状Ａｌ_３Ｆｅ相（底心单斜结构），部分长大但仍保持球状和底心正方结构过饱和固溶于α－Ａｌ基体中的Ｔｉ和Ｃ则以ＴｉＣ形式弥散析出。     

Fe－28Al合金中相转变

应用电镜及Ｘ射线衍射技术研究了含Ｃｒ及不含Ｃｒ的Ｆｅ－２８ａｔ．－％Ａｌ合金中相变结果表明，１０８０℃淬火过程中，Ｂ２结构热畴已开始形成；缓冷通过Ｂ２相区，沿晶界出现α相；对Ｆｅ－２８Ａｌ－５Ｃｒ合金还出现细小的ＣｒＮ相沉淀，板状合金中Ｂ２→Ｄ０３是一缓慢转变过程．     

渗铝NiAl－20％Fe金属间合金的高温热腐蚀

本文研究了在９５０℃空气中，表面涂Ｎａ_２ＳＯ_４盐膜的条件下，ＮｉＡｌ，ＮｉＡｌ－２０％Ｆｅ及渗铝后的高温热腐蚀行为。在热腐蚀过程中，ＮｉＡｌ合金表面能形成Ａｌ_２Ｏ_３膜，显示出一定的耐蚀性能。但Ａｌ_２Ｏ_３膜易开裂，Ａｌ_２Ｏ_３膜的溶解及开裂会引发合金发生快速热腐蚀；２０％Ｆｅ的加入则使ＮｉＡｌ合金的耐蚀性能显著变差，合金表面不能形成单一的Ａｌ_２Ｏ_３膜；渗铝处理可以明显提高ＮｉＡｌ－２０％Ｆｅ合金的耐蚀性能，且渗铝涂层的耐蚀性能优于ＮｉＡｌ合金，这与铝化物涂层中的Ａｌ含量较高，Ａｌ_２Ｏ_３膜的开裂倾向较小有关。     

NiAl—Fe合金的双向形状记忆效应

ＮｉＡｌ—Ｆｅ合金的双向形状记忆效应ＮｉＡｌ－Ｆｅ双相（β＋γ）形状记忆合金具有良好的室温韧性。高温淬火合金经过加工热处理之后的形状回复率高达９０％。影响该合金单向形状记忆效应的因素，有淬火温度、含在β相基体中的γ相数量和晶粒尺寸。但尚未见到有关该合...     

Fe—28A1合金中相转变

应用电镜及Ｘ射线衍射技术研究了含Ｃｒ及不含Ｃｒ的Ｆｅ－２８ａｔ．－％Ａｌ合金中相变结果表明，１０８０℃淬火过程中，Ｂ２结构热畴已开始形成；缓冷通过Ｂ２相区，沿晶界出现α相；对Ｆｅ－２８Ａｌ－５Ｃｒ合金还出现细小的ＣｒＮ相沉淀，板状合金中Ｂ２→Ｄ０３是一缓慢转变过程。     

Effects of Heat Treatment and Thermal Cycling on Martensitic Transformation Behavior of Ni59Al11Mn30 High Temperature Shape Memory Alloy

A reversible martensitic transformation (MT) takes place during cooling and heating in the solution quenched and the solution quenched plus aged Ni59Al11Mn30 alloy. The MT temperature increases with increasing solution temperature. The excellent MT characteristics can be obtained from a process of 1000℃ solution quenched plus 400℃ aged. Follow this process, the MT start temperature (Ms) and the reverse MT finish temperature (Af) are 469℃ and 548℃,respectively. The martensitic stabilization effect in the solution quenched and aged Ni59Al11Mn30 alloy is observed as an increase in the Af temperature of the first reverse MT during thermal cycles. This stabilization effect vanishes from the second thermal cycle. Thermal cycling can enhance the stability of the reversible MT. The microstructure of the quenched Ni59Al11Mn30 alloy consists of martensite (M) and gamma phase. The volume fraction of gamma phase is about 40%. The substructure of M and gamma phase is twins and dislocations, respectively. The hardness of M is higher than that of gamma phase. After aging treatment the basic phases of alloy do not change, but the hardness of the phases increases.     

La0.7Mg0.3Ni2.55-xCo0.45Alx(x=0～0.4)贮氢合金的循环稳定性

为了提高La-Mg-Ni系贮氢合金的循环稳定性,以Al部分替代Ni,采铸造及快淬工艺制备了La0.7Mg0.3Ni2.55-xCo0.45Alx(x=0,0.1,0.2,0.3,0.4)电极合金,研究了Al替代量及快淬工艺对合金微观结构及电化学循环稳定性的影响。X射线衍射分析结果表明:铸态及快淬态合金具有多相结构,包括(La,Mg)Ni3相、LaNi5相和一定量的LaNi2相;Al替代使铸态合金中LaNi2相的量显著增加,但对快淬态合金中LaNi2相的相丰度影响不显著。电化学测试结果表明:随Al替代量的增加,合金的循环寿命大幅度提高;快淬处理可以提高合金的循环寿命,但随Al替代量的增加,淬速对循环寿命的影响减小。     

Fragility and glass forming ability of Al-Ni-Ce alloy melts

The fragility of Al-Ni-Ce alloy melts with three kinds of different compositions, Al85Ni10Ce5,Al85Ni8Ce7, Al85Ni5Ce10 (mole fraction, %), was studied using oscillating-vessel viscometer and differential scanning calorimetry. Their fragility parameters obtained from experiments and theoretic calculation are: 238, 228 and 335 respectively. The results indicate that these three kinds of Al-Ni-Ce alloy melts are very fragile liquids, which kinetically show strong non-Arrhenius behaviour in the Angell plot, so they have poor glass forming ability (GFA).The alloy melt AI85NiSCe10 has the largest fragility parameter among the three alloy melts. In the preparation of rapidly quenched amorphous ribbons, AI85Ni10Ce5 and AI85Ni8Ce7 can gain amorphous ribbons when the rotate speed of the roller reaches 800r/min, while for Al85Ni5Ce10 it must exceed 1 000r/min.     

Homogenizing behaviour in a hydrogen-absorbing LaNi4.55Al0.45 alloy through annealing and rapid quenching

Homogenizing behaviour in a hydrogen-absorbing alloy with a composition of LaNi_4.55Al_0.45 through annealing and rapid quenching was investigated to improve its equilibrium characteristics with hydrogen. Annealing has an effect on homogenizing the Al distribution in the dominant phase of CaCu₅ structure and decreasing the plateau slope in the P-C isotherms. The rapidly quenched alloy exhibited a flatter but narrower plateau region than the induction-melted and annealed alloy, which became wider after short-time annealing for 7.2 ks at 1323 K. The effect of the annealing in the rapidly quenched alloy was attributed to a decrease in lattice defects introduced by the rapid quenching process.     

Al含量对热轧FeMnCoCr系高熵合金组织和性能的影响

研究了Al含量对(Fe₅₀Mn₃₀Co₁₀Cr₁₀)_100-xAl_x高熵合金微观组织、变形机制和拉伸性能的影响。采用真空电弧熔炼炉制备合金铸锭,对合金进行压下率为80%的热轧火淬,利用SEM和EBSD对合金的组织结构进行了分析。结果表明,随着Al含量(原子分数,下同)由0%增加到6%,热轧淬火后合金组织由FCC+HCP双相转变成FCC单相,Al含量为8%时产生了BCC相;随着Al含量由0%增加到6%,在拉伸过程中TRIP效应受到抑制,TWIP效应明显增加,合金的屈服强度变化不大,抗拉强度稍有降低,断后伸长率显著增加,当Al含量为6%时断后伸长率达到最高,为79%。     

Al-6.3Zn-2.8Mg-1.8Cu铸造铝合金的组织和室温力学性能

研究了Al-6.3Zn 2.8Mg-1.8Cu铸造铝合金的组织和室温力学性能.研究表明,在金属型铸造条件下,Al-6.3Zn-2.8Mg-1.8Cu合金的铸态组织为近等轴晶,相组成为α（Al）基体、枝晶间α（Al）+η（MgZn₂）共晶、晶内游离η相（MgZn₂）、少量T相（Mg₃Zn_xCu₃-_xAl₂）及少量颗粒状Al₇Cu₂Fe.固溶处理后,原铸态组织中的η（MgZn₂）相大部分溶解消失,但形成新的沿晶界分布的S相（Al₂CuMg）.实验确定了固溶态Al-6.3Zn-2.8Mg-1.8Cu合金较优的单级和双级时效工艺.与单级时效工艺相比,采用双级时效工艺处理后,抗拉强度由480 MPa增加至490 MPa,延伸率由0.2%增加至2.2%.     

Effects of cold roll and heat treatments on anomalous thermal behavior in Fe100−xAlx(x = 5–30) alloys

DSC measurements were carried out for various Fe_100−xAl_x(x = 5–30 at%) alloys to clear the effects of cold roll and quenching rate from 1173 K. In the case of cold roll free specimens, an exothermic peak was observed at around 530–560 K in quenched specimens and no peaks in slowly cooled specimens. The peak temperature and its exothermic heat depended on the alloy composition. The maximum exothermic heat was obtained for a 25 at% Al alloy and its value were about 1200 J/mol. The peak in a 5 at% Al alloy was remained as a future work. The exothermic heat was affected by the quenching temperature in alloys above 15 at% Al. The peak temperature was decreased by decreasing the quenching temperature. In a 15 at% Al alloy, the peak became negligibly small by quenching from 1023 K. The activation energies in cold roll free specimens were evaluated from the Kissinger analysis and they were 134, 108, 133 and 110 kJ/mol for 15 at% Al, 20 at% Al, 25 at% Al and 30 at% Al alloys, respectively. On the other hand, cold rolled specimens showed an exothermic peak at around 470 K, independently of the cooling rate. Their exothermic heats and temperatures were comparable order to those of furnace cooled and water quenched specimens. The present results suggested that origin of exothermic peaks of all alloys were same in nature and atomic ordering may be related to the exothermic behavior at relatively low temperatures.     

CONCENTRATION DISTRIBUTION OF ALLOYING ELEMENTS IN SURFACE LAYER OF Ti ALLOY MELTS

The concentration distribution of alloying elements such as Al,Sn,V,Si and Mo in surfacelayer of quenched Ti alloy melts(TC4,TA 7 and TC9)has been determined by EPMA.Ti al-loy samples were melted and evaporized by electron beam in water cooled copper curcible.Theactivity coefficient of alloy elements in Ti alloy melts are:γ_(Al)=0.009—0.018 and γ_(Sn)=0.066—0.123 at 1921—2106℃;γ_V=0.713 at 2021℃;γ_(Si)=0.020 and γ_(Mo)=0.913 at 1921℃.Therate controlling steps of the evaporation of alloying elements Al,Sn,V,Si and Mo from Ti al-loy melts have been discussed with the data of evaporation activation energies of such alloy el-ements.     

Simulation of early-stage clustering in ternary metal alloys using the phase-field crystal method

Phase-field crystal methodology is applied, for the first time, to study the effect of alloy composition on the clustering behavior of a quenched/aged supersaturated ternary Al alloy system. An analysis of the work of formation is adapted from a methodology developed in Fallah et al. to describe the dislocation-mediated nucleation and growth mechanisms of early clusters in binary alloys [Phys Rev B 2012;86:134112]. Consistent with the experiments, we demonstrate that the addition of Mg to an Al–1.1Cu alloy increases the nucleation rate of clusters in the quenched/aged state by increasing the effective driving force for nucleation, enhancing the dislocation stress relaxation and decreasing the surface energy associated with the Cu-rich co-clusters of Cu–Mg. Furthermore, we show that it is thermodynamically favorable for small subcritical clusters to have higher affinity for Mg than larger post-critical Cu-rich clusters, particularly depicting a two-stage clustering phenomenon.