2024系列铝合金粗大夹杂相的微观结构研究

本文利用X射线能谱分析、会聚束电子衍射和常规电子衍射对2024系列铝合金粗大夹杂相的结构类型和成分进行了研究。所有夹杂相的合金元素均部分地被其它元素所取代,使粗大夹杂相的成分稍偏离于理想的三元化合物。粗大夹杂相中含量最多的是体心立方α-Al_(12)(FeMn)_3Si,空间群为Im 3,点阵常数α=1.25nm;其次是Cu_2FeAl_7,空间群为P4/mnc,点阵常数α=0.6336nm,c=1.487nm;还有少量的属简单立方的α-Al_(12)Fe_3Si,空间群为Pm 3,点阵常数α=1.27nm。     

Ni—Al系、Fe—Al系和Ti3Al金属间化合物研究

简要介绍了金属间化合物的熔炼与铸造工艺。论述了Ni-Al系（包括NiAl和Ni3Al)、Fe-Al系（包括Fe3Al和FeAl)及Ti3Al基金属间化合物高温结构材料的研究现状和发展动态,分析了上述合金存在的问题及解决办法,介绍了它们在不同领域的潜在应用。     

微量Sc在Al—Mg合金中的作用

研究了微量Sc对Al-Mg合金显微组织与拉伸性能的影响,结果表明,微量Sc在Al-Mg合金中主要以初生Al3Sc和次生Al3Sc两种形式存在,初生Al3Sc是合金在凝固过程中形成的,可成为有效的非均质晶核,大大细化合金的铸态晶粒,次生Al3Sc是合金铸锭在工艺加热过程中析出的,有效地钉扎位错和亚晶界,稳定亚结构并强烈抑制合金的再结晶,具有亚结构强化和直接析出强化作用,因此,加入Sc后的Al-Mg合金的强度大大提高,并且表现出良好的强塑性配合。     

Al—Ti—C铝合金晶粒细化剂的研究进展

对新型铝合金晶粒细化剂Al-Ti-C的研究进展,制备方法,细化机理进行了述评。Al-Ti-C晶粒细化剂中的异持形核核心TiC有助于Al3Ti形核,而α－Al又包在Al3Ti外面,形核几率大相同添加量的Al-Ti-B,细化效果更好,异质形核核心TiC有助于Al3Ti形核,而α－Al3Ti外面,形核几率大于相同添加量的Al-Ti-B,细化效果更好。     

一种Ti—Mo—Nb—Al合金的固溶态显微组织研究

通过对金相显微组织观察、Ｘ射线衍射和透射电镜分析,研究了Ｔｉ－Ｍｏ－Ｎｂ－Ａｌ合金在不同固溶温度雀火后的组织和相变规律。结果表明：该合金在相变以下的淬火组织由α,β相和淬火ε相及Ｔｉ５Ｓｉ３相组成,随温度升高,α相减少;在相变点以上的淬火组织为β相和少量淬火相及Ｔｉ５Ｓｉ３相。     

Co—Ni—Al—Ti系L21／L12型双相金属间化合物合金热处理显微组织研究

对由L21型（Co,Ni）2AlTi和L12型（Co,Ni)3（Al,Ti）两种有序相组成的Co-Ni-Al系新型金属间化合物高温结构实验用合金进行了不同制度的热处理,并对相应的显微组织特征进行了分析研究。找到了控制显微组织以优化性能的热处理参数。     

Ti—3Al—2.5V合金的热稳定性研究

Ｔｉ—３Ａ１—２．５Ｖ合金是美国６０年代研制的一种近α的α＋β型钛合金，最初是作为焊接管材和无缝管材而研制的．７０年代末该合金管材已在Ｆ１４、Ｆ１５、Ｂ１、波音７４７等飞机上应用．关于 Ｔｉ—３Ａ１—２．５Ｖ合金热稳定性研究，未见国外报道．为了了解该合金的热稳定性能，以Ｔｉ—３Ａ１—２．５Ｖ合金管、棒材为试验原料，研究了该合金在 １２５℃～ ５００℃温度区间，无应力作用时，分别热暴露４００ｈ～２０００ｈ后材料的热稳定性能．ｌ试验材料及方法１．１试验材料 试验材料选用经真空退火的１２ｍｍ×０．９ｍｍ、…     

快速凝固Al—Ti—Fe系合金的组织演化

采用单辊旋铸技术制备Al-2.5Ti-2.5Fe,Al2.5Ti-2.5Fe-2.5V和Al-2.5Ti-2.5Fe-2.5Cr(at%，下同）合金薄带，利用X射线衍射（XRD）和透射电镜（TEM）分析了这些合金的急冷态和退火态组织。结果表明：快速凝固Al-2.5Ti-2.5Fe合金急冷态组织中存在Al3Ti和Al5Ti2两种初生相，快凝合金经400℃退火10h后，组织中出现了Al13Fe4相，在450℃退火，组织中析出了弥散Al3Ti相；快速凝固Al-2.5Ti-2.5Fe-2.5V合金急冷态组织中存在Al11V相和Al80V20相，400℃退火10h后，初生Al11V相转变为Al80V20相，且固溶在α-Al基体中的Ti,Fe以Al23Ti9相和Al13Fe4相的形式析出；快速凝固Al-2.5Ti-2.5Fe-2.5Cr合金急冷态组织中存在Al3Ti和Al13Cr2两种初生相，快凝合金经300℃退火10h后，组织中析出了Al13Cr2和Al3Ti两种弥散相，400℃退火10h时后组织中出现了Al13Fe4相。     

新的低成本钛合金—TIMETAL 62S

简要介绍了钛铝系金属间化合物的发展背景，着重阐述了目前α２－Ｔｉ３Ａｌ基、γ－ＴｉＡｌ基及δ－ＴｉＡｌ３基合金的发展状况、总结了近年来为了获得钛铝系金属间化合物的良好综合机械性能尤其是室温塑性，国内外研究者所采用的一系列方法。     

Ti—Co（Ni）—Al系合金的超塑性研究

研究了Ti-Co(Ni)-Al系合金的低温高速超塑性行为,表明该合金系在很宽的应变速率范围内((?)=10~(-1)～10~(-3)S~(-1))和较低的变形温度下(700—750℃)具有良好的超塑性。Ti-Co-Al合金最高延伸率大于2000%,m值为0.58—0.70。认为超细的α晶粒和均匀弥散的第二相粒子Ti_2Co(Ti_2Ni)等是有利于合金超塑性变形的显微组织因素。用TEM和SEM对超塑拉伸过程中合金显微组织的变化进行了观察,发现晶界滑动和晶粒转动是Ti-Co(Ni)-Al系合金超塑变形的主导机制,而位错运动产生的晶内滑移是其重要的伴随机制。此外由于Co,Ni等元素在钛中具有很高的扩散速率,促进了Ti-Co(Ni)-Al系合金超塑变形时的晶界和晶内滑移。     

MICROSTRUCTURE STUDY OF CONSTITUENT PHASES IN 2024 SERIES Al ALLOYS

X-ray microanalysis,convergent beam electron diffraction(CBD)and selected area electrondiffraction(SAD)studies on the structures and compositions of the constituent phases in2024 series Al alloys have been conducted.Partial substitution of alloying elements is found tooccur in all the constituent phases,which cause small deviations from the stoichiometric com-positions reported in these ternary compounds.The dominant phase is α-Al_(12)(FeMn)_3Si whichhas a body center cubic crystal structure with the Im■ space group and a=1.25 nm.The nextdominant phase is Cu_2FeAl_7 which has a primitive tetragonal crystal structure with theP4/mnc space group and a=0.6336 nm,c=1.487 nm.The minor phase is α'-Al_(12)Fe_3Si hav-ing α primitive cubic crystal structure with the Pm■ space group and α=1.27 nm.     

钛合金蜂窝夹层结构钎焊界面的价电子结构分析

对TC1钛合金蜂窝夹层结构试件的钎焊界面组织进行观察、分析确定界面生成相的晶体结构,采用EET理论中BLD方法和平均原子模型,计算分析了钎焊界面价电子结构.从原子间结合力的角度分析了钛合金蜂窝夹层结构钎焊界面的价电子结构,探讨了界面结构与力学性能的本质关系.钎焊过程中界面处生成了六方晶体结构TiNi₃(Cu,Zr)化合物和体心立方结构Ti(Ni,Zr,Cu)相.从原子间成键角度,最大共价电子数和晶格电子数分别反映了晶体的强度和塑性.TiNi₃(Cu,Zr)化合物和Ti(Ni,Zr,Cu)相的最大共价电子数分别为0.055 8和0.303 7,晶格电子分别为0.993 5和1.392 8,而界面处基体的最大共价电子数和晶格电子数分别为0.305 9和1.397 3.因此,与TiNi₃(Cu,Zr)化合物相比,Ti(Ni,Zr,Cu)和钛固溶体晶胞不仅具有较高的强度,还具有相对良好的塑性,而TiNi₃(Cu,Zr)化合物相的存在和连续分布不利于钎焊界面的强度和塑性.     

Constitution of the ternary system Al-Ru-Ti (Aluminum-Ruthenium-Titanium)

Phase relations in the ternary system Al-Ru-Ti were studied on arc-melted alloys and specimens annealed at 1100 °C, 950 °C, and 800 °C employing optical and electron microscopy, x-ray diffraction, and electron probe microanalysis. The results, in combination with an assessment of all literature data available, were used to construct liquidus and solidus surfaces, a series of isothermal sections, and a Schulz-Scheil diagram monitoring solidification (crystallization) in thermodynamic equilibrium. The crystal structure of the ternary G-phase was determined by x-ray single crystal diffraction to be a filled variant of the Th₆Mn₂₃-type (space group Fm3m). Furthermore, a new ternary compound with AuCu₃-type structure was detected.     

Constitution of the ternary system Al-Ru-Ti (Aluminum-Ruthenium-Titanium)

Phase relations in the ternary system Al-Ru-Ti were studied on arc-melted alloys and specimens annealed at 1100 °C, 950 °C, and 800 °C employing optical and electron microscopy, x-ray diffraction, and electron probe microanalysis. The results, in combination with an assessment of all literature data available, were used to construct liquidus and solidus surfaces, a series of isothermal sections, and a Schulz-Scheil diagram monitoring solidification (crystallization) in thermodynamic equilibrium. The crystal structure of the ternary G-phase was determined by x-ray single crystal diffraction to be a filled variant of the Th₆Mn₂₃-type (space group Fm3m). Furthermore, a new ternary compound with AuCu₃-type structure was detected.     

扫描间距对选区激光熔化IN718合金微观组织的影响

通过选区激光熔化(SLM)技术制备了IN718合金,利用X射线显微镜、X射线衍射仪、扫描电镜和电子背散射衍射等技术分析了IN718合金的致密性、相组成和晶粒形态以及取向关系。结果表明:SLM成形IN718合金的物相组成为面心立方结构的γ-Ni相与体心四方结构的γ″相,晶粒沿构建方向呈柱状晶。当激光扫描间距为100 μm时合金的致密度达到最高,当激光扫描间距为90 μm时,合金沿构建方向形成强<001>织构。     

Refining performance of Al–3Ti–0.2C–5Sr on A356 alloy and electron microanalysis of ternary Al–Ti–Sr phases

The effect of Al-3Ti-0.2C-5Sr(wt%) grain refiner on the refining performance and modification of A356 alloy was investigated using optical microscope(OM).The morphology and crystal structure of ternary Al-Ti-Sr phases in Al-3Ti-0.2C-5Sr refiner were analyzed by scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The results show that the ternary Al-TiSr phases in Al-3Ti-0.2C-5Sr refiner can promote the grain refining efficiency of A356 alloy.The ternary Al-Ti-Sr phases co-exist in two morphologies,i.e.,blocky-like phase and surround-like phase,besides,which both have the same chemical composition of Al_(34)Ti_3Sr.The crystal structure of Al_(34)Ti_3Sr is face-centered cubic,and the lattice parameter is determined to be about 1.52 nm.     

A modulated structure derived from the σ phase in the Mo–Ni–Re system

The crystal structure identification of a new Mo–Ni–Re phase was carried out. The chemical characterisation of the studied composition was performed with the help of electron probe microanalysis (EPMA) whereas X-ray diffraction (XRD) and single crystal diffraction techniques were used for structural characterisation. The characterisation results revealed that this new Mo–Ni–Re phase has a modulated σ phase structure.     

A ternary linear compound T2 and its phase equilibrium relationships in Mg–Zn–Nd system at 400 °C

The composition and the crystal structure of the phases in the alloys of Mg–Zn–Nd system at 400 °C have been studied by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), X-ray diffraction (XRD) and selected area electron diffraction (SAED) of transmission electron microscopy (TEM). The phase equilibrium relationships have been identified. As a result, a linear ternary compound T₂ phase has been identified. The general chemical formula of T₂ phase is (Mg, Zn)_11.5Nd and the crystal structure of that is C-centered orthorhombic. As the results, the other three ternary compounds T₁ phase, T₃ phase and T₄ phase have also been identified. The partial isothermal section of phase diagram of Mg–Zn–Nd system at 400 °C has been established.     

UFeGa5单晶生长及晶体结构研究

采用镓自助熔剂的方法生长出了UFeGa5单晶,采用X射线衍射技术和Rietveld方法对UFeGa5晶体结构进行了研究。结果表明:生长出的UFeGa5单晶体结构完整,结晶性好。UFeGa5具有HoCoGa5型四方结构,空间群为P4/mmm(No.123),其晶格常数为a=0.42533(2)nm,c=0.67298(3)nm,并得到了透射电镜(TEM)实验验证。     

Investigation of the titanium–indium system

The phase diagram of the Ti–In system was determined using DTA, XRD and EDX analyses. The existence of the phases Ti₂In₅ [Mn₂Hg₅ type structure, space group P4/mbm, a=0.99995(3), c=0.29960(2) nm] and Ti₃In [Ni₃Sn type structure, space group P6₃/mmc, a=0.5978(1), c=0.4812(1) nm] was confirmed. The phase previously labeled Ti₃In₂ was found to exist in a narrow homogeneity region near Ti₅₆In₄₄. Rietveld refinement of the XRD powder pattern yielded solutions compatible with a Cu₃Au-type or a BiIn-type crystal structure, but not with a CuAu-type crystal structure. Furthermore, at 38.5 at.% In, a new phase was observed having a γ-brass related crystal structure [Ti₈In₅, space group , a=0.99578(6) nm]. The intermetallic phases were formed by a cascade of peritectic reactions ending in a eutectic at >99 at.% indium between Ti₂In₅ and (In) at 0.4 K below the melting temperature of pure indium.