Ti含量对Nb-Si-Mo-Ti系合金组织性能的影响

为研究Ti含量对Nb-Si系合金组织及性能的影响,以机械球磨和SPS烧结技术结合的方法制备了Nb-16Si-10Mo-x Ti(x=0,2,4,6,8,10)合金,对x不同时的合金在室温、1200℃时的组织及力学性能进行探究。结果表明:Ti含量增多,Ti ss韧性相逐渐增多并聚集,组成相包括Nb ss、Nb 5 Si 3和Ti ss相。室温下,合金弯曲强度、断裂韧性等有所提高,硬度下降,抗压强度先降后增,x=0时,抗压强度最高为2300 MPa,而Nb-Si-Mo-Ti系合金抗压强度最高为2200 MPa,且断裂方式由脆性断裂转变为复合断裂。1200℃下,抗压强度先降后增,x=0时,最高为605 MPa,随Ti含量增加,Nb-Si-Mo-Ti系合金抗压强度最高可达470 MPa,同时有较好塑韧性。1200℃压缩后,组织细化,韧性相沿垂直于压缩方向拉长,硬脆相则被挤压到韧性相内部或表面分布。

Precipitation of α_2 Phase in α+β Solution-Treated and Air-cooled Ti-Al-Sn-Zr-Mo-Si-Nd Alloys

A series of Ti-Al-Sn-Zr-Mo-Si-Nd alloys with various content of Al were solution treated in α+β phase field and air-cooled. The precipitation of a2 phase in cooling was investigated by transmission electron microscopic analysis The precipitation characteristic of α2 phase was discussed. The precipitation of α2 phase would proceed by the nucleation and growth of α2 phase dependent on the diffusion of Al atoms. And a comparison on the difference of precipitation of α2 phase was carried out under the conditions of air-cooling and quenching in water. The investigation showed that the air-cooling and even quenching could supply enough time for the precipitation and growth of α2 phase when Al content reached a certain value even though far away from the stoichiometric composition of Ti3Al.

Modification and refinement mechanism of Mg_2Si phase in Sr-containing AZ61-0.7Si magnesium alloy

The effect of Sr on modification and refinement of the Mg 2 Si phase in an AZ61-0.7Si magnesium alloy has been investigated and analyzed.The results indicate that Sr can effectively modify and refine the Chinese-script shaped Mg2Si phase in the AZ61-0.7Si alloy.By adding 0.06wt.%-0.12wt.%Sr to AZ61-0.7Si alloy,the Mg2Si phase in the alloy can be changed from the initial coarse Chinese-script shape to fine granule and/or irregular polygonal shapes.Accordingly,the Sr-containing AZ61-0.7Si alloy exhibits higher tensile and creep properties than the AZ61-0.7Si alloy without Sr modification.The mechanism on modification and refinement of the Mg2Si phase in Sr-containing AZ61-0.7Si alloy is possibly related to the following two aspects:(1)adding Sr may form the Al4Sr phase which can serve as the heterogeneous nucleus for the Mg2Si particles and/or(2)adding Sr may lower the onset crystallizing temperature and increase the undercooling level.

Ordering of the α-Fe(Si) Crystallization Phase in Annealed Fe_(73.5)Cu_1Mo_3Si_(13.5)B_9 Alloy

The ordering of the α-Fe(Si) crystallization phase in annealed Fe73.5Cu1Mo3Si13.5B9 alloy has been studied using XRD method. The α-Fe(Si) phase in Fe73.5Cu1Mo3Si13.5B9 alloy annealed at 460℃ for 1 h consists of the DO3-type ordered region with spherical shape and disordered region. The size of DO3 ordered region increases with the annealing temperature. When the annealing temperature is 560℃, the size of the ordered region in the α-Fe(Si) grain is 14.0nm,which is nearly as large as that of the α-Fe(Si) grain (14.2 nm) and the degree of order of the α-Fe(Si) phase is about 0.78. When Fe73.5Cu1 Mo3Si13.5B9 amorphous alloy is annealed at 520℃， with the increment of the annealing time, the shape of the DO3 ordered region in the α-Fe(Si) phase is spheroidal at the beginning of the annealing and becomes spherical and has asize of 12.8 nm when the annealing time is 60 min. In addition, the DO3 superlattice lines of the α-Fe(Si) phase will vanish if Fe73.5Cu1Mo3Si13.5 B9 amorphous alloy is annealed for 1 h at 750℃.

Characteristics of Faigue Crack Initiation in Ti-5Al-4Sn-2Zr-1Mo-0.7Nd-0.25Si Alloy

The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25Si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue crack initiation than the matrix at lower stress.

CRYSTALLIZATION AND HARDNESS CHANGE OF RAPIDLY SOLIDIFIED Fe-C-Si-Mo ALLOYS

Crystallization behavior of rapidly solidified Fe-C-Si-Mo alloy ribbons made by single rol- ler method together with their changes in phase and hardness have been studied by X-ray diffraction and SEM.The results show that the alloys attribute their very high Vickers hardness to numerous fine carbides formed during crystallization.

Effect of Ageing on Martensitic Transformation and Shape Memory Effect of Fe-Mn-Si-Co-Mo Alloy

This paper discusses the effect of ageing on the thermally induced martensitic transformation and its reverse transformation and shape memory effect of Fe-24Mn-5Si-8Co-4Mo shape memory alloy:the precipitation of Fe 2Mo particles increases the hardness and strength of the alloy as ageing goes on;ageing increases the transformation temperatures;ageing improves,the SME of the alloy so remarkably that a maximum shape recovery ratio is obtained while ageing at 600℃.

Effect of Al Content on Precipitation of α_2 Ordered Phase in Ti-Al-Sn-Zr-Mo-Si-Nd Alloys

The precipitation characteristics of the α2 ordered phase in Ti-AI-Sn-Zr-Mo-Si-Nd alloys with various content of Al, under different aging conditions, were investigated. The distribution and size of the α2 ordered phase changed with temperature and Al content. The dislocations were the only places where the α2 ordered phase could precipitate at higher temperature near the critical transformation temperature for each alloy experimented. With the addition of Al content, the critical transformation temperature of α2 ordered phase increased. When the aging temperature was relatively low (650℃), the precedent precipitation of α2 ordered phase took place in primary a phase at the early stage of aging, in the duplex microstructure (the primary a with the transformed (3) of the alloys with lower Al content. But after certain aging time (50 h), the size of α2 particles was almost equal in both the primary a and the transformed β. And no obvious growth of α2 particles could be observed after 50 h.

Hot deformation behavior and microstructure evolution of titanium alloy Ti-Al-Zr-Sn-Mo-Si-Y

Samples of Ti-Al-Zr-Sn-Mo-Si-Y alloy were compressed on the Gleeble-1500 heat stimulation machine. The compression test was carried out in the temperature range from 800 ℃ to 1 100 ℃ and strain rate range from 0.001 s-1 to 10 s-1. Stress-strain behavior and variation of microstructure of the alloy during hot compression were investigated. The experimental results show that the alloy is sensitive to temperature and strain rate,and the flow softening behavior is more obvious with the decrease of deformation temperature. At higher strain rate,discontinuous yielding is observed in β phase region. When deformed in α+β phase region,with the increment of deformation temperature,the lamellar α structures globularization is more quick and more uniform. When deformed in β phase region,coarse β grains can be got because of high deformation temperature.

ICP-AES法测定铝合金中Fe、Si、Mo、Zr、Ti、Y的研究

本文采用ＩＣＰ－ＡＥＳ法测定了铝合金中的Ｆｅ、Ｓｉ、Ｍｏ、Ｚｒ、Ｔｉ、Ｙ，并对样品的溶解方法、共存元素间的光谱干扰、内标元素的选择等进行了研究，建立的分析方法简便快速，有较好的精密度和准确度。

Co-Mo-Cr-Si合金组织及其耐铝液腐蚀性能

通过扫描电子显微镜和能谱仪(SEM-EDS)以及X射线衍射仪(XRD)等研究不同含量的Mo、Cr和Si对Co-Mo-Cr-Si合金的组织及其700℃耐铝液腐蚀性能的影响。结果表明:在实验范围内,当w(Si)<2.8%时,基体为FCC-Co;而当w(Si)≥2.8%时,基体转变为HCP-Co。随Mo和Si含量增加,Laves相比例增加。在本工作中CoMo4Cr23.8Si0.6合金耐腐蚀性能最好,但由于是单一的固溶体相,基体很软。具有高硬度的CoMo28.5Cr16.7Six合金随着Si含量的增加,其硬度随之增加,耐腐蚀性也随之提高,腐蚀产物主要是(Co,Mo,Cr)2Al9和(Cr,Mo)7Al45。Mo含量较多时主要生成(Mo,Cr)Al5,Cr元素含量较多时主要生成(Cr,Mo)2Al13。

Mo-Si-B三元系金属间化合物超高温结构材料研究进展

Mo-Si-B三元系金属间化合物合金具有高熔点,存在韧脆转变,且有良好的高温抗氧化性和相对低的密度,是极具潜力的超高温结构材料;但是也存在低温脆性大,高于1 300℃时高温强度尤其抗蠕变能力不足的缺点,阻碍了其应用。本文从制备工艺、组织结构、高温抗氧化性能、力学性能和合金化等几个方面综述了T2,Moss+Mo3Si+T2和T1+T2+Mo3Si三个相区合金的研究现状。并且指出,原位合成制备技术和"少量多元"合金化是Mo-Si-B三元系合金未来的发展方向。

ICP-AES测定铝合金中Mg、Be、Mn、Mo、Fe、Ti、Si和Zn

采用ICP-AES同时测定铝合金中合金元素和杂质元素,优化ICP光谱仪的工作条件,测定回收率96%—106%,RSD0.28%—6.26%,结果令人满意。

基于Al合金化的β-Mo(Si,Al)_2自蔓延高温合成

为了研究添加Al粉对自蔓延高温合成β-Mo（Si，Al）2的影响，以Si、M0和Al粉为原料，按照化学式Mo（Si1-xAl）2（x分别取0、0．1、0．2、0．3、0．4，即Al取代Si物质的量依次为0、10％、20％、30％、40％）配料，采用自蔓延高温合成制备了不同Al含量的β-Mo（Si，Al）2，并利用X射线衍射仪和扫描电镜对合成产物进行了相组成和产物形貌分析。结果表明：Al的加入有利于自蔓延反应进行得更加完全，在自蔓延过程中，Al进入到MoSi2晶格中，发生Al、Si取代，当Al取代Si物质的量达到40％时，仍能实现Al的合金化，生成高温相β-Mo（Si，Al）2，并且随着Al的添加会使自蔓延合成产物的晶格发生严重变形。通过SEM观察发现：加入Al粉的合成产物形貌都呈现出小颗粒的聚集状态，且小颗粒为球形或接近等轴状，颗粒平均粒径为2—5μm，说明自蔓延合成产物的形貌继承了Mo粉的原始形貌，而与Al粉加入量没有明显关系。

LED用Sr_((1-1.5x))Mo_(0.8)Si_(0.2)O_(3.8)∶Eu_x^(3+)红色荧光粉的制备及其荧光性能

通过高温固相法合成了LED用红色荧光粉Sr(1-1.5x)Mo0.8Si0.2O3.8∶Eu3x+(x=0.1,0.2,0.3,0.4,0.5)。通过XRD、激发光谱和发射光谱测试了材料的物相组成以及发光性能。x=0.1样品的XRD谱与JCPDS 08-0482(SrMoO4)的标准卡片相同。Eu3+代替晶格中Sr2+的位置成为发光中心。随着Eu3+含量x的增加,593 nm处的5D0-7F1跃迁和614 nm处的5D0-7F2跃迁发射强度会相互转换:当x≤0.4时,以磁偶极5D0-7F1跃迁为主,发射橙色光;而当x=0.5时,以电偶极5D0-7F2跃迁发射为主,发射红光。可能是过量掺杂的Eu3+离子,只能存在于晶格空位形成缺陷,无法占据SrMoO4中Sr2+的格位中,Eu3+在晶格中占据非对称中心的格位,导致电偶极跃迁变成允许跃迁,从而增加了5D0-7F2跃迁,减弱了5D0-7F1跃迁。因此,可以通过调节激活剂的含量获得不同发光色的荧光粉。Eu3+掺杂的硅钼酸锶体系,614 nm激发下,在368 nm处出现宽的基质吸收峰和467 nm处7 F0-5 D2的跃迁峰,且这2处的吸收峰在x=0.5时比x=0.4时强3倍左右。材料能非常好的吸收368 nm波长的光,产生颜色可调的橙红色。与近紫外光LED芯片匹配良好。

明效Fe-Mn-Si-Co-Mo合金中应力诱发马氏体的逆相变与形状记忆效应

研究了时效对ＦｅＭｎＳｉＣｏＭｏ 合金的临界屈服应力、应力诱发马氏体逆转变以及形状记忆效应的影响． 结果表明，随着时效温度的升高，室温下的母相屈服应力与应力诱发马氏体相变临界应力之差增大，应力诱发马氏体逆转变温度Ａｓ 和Ａｆ 升高，而形状记忆效应在６００ ℃时效时出现峰值． 电镜组织观察表明，时效温度高于６００ ℃时，应力诱发马氏体中全位错密度增大，使应力诱发马氏体稳定性提高．

Ti-Al-Sn-Zr-Mo-Si系高温钛合金的制备及其力学性能研究

在Ti-Al-Sn-Zr-Mo-Si系近α合金的基础上,通过改变Sn的含量,制备出了4种不同Sn含量Ti-6Al-xSn-4Zr-1Mo-0.8Si-0.5B高温钛合金(x=2,4,6,8)。采用XRD、SEM和TEM对样品的结构和组成进行表征,采用电子万能材料试验机对样品的力学性能进行测试分析。XRD分析可知,4种不同Sn含量的高温钛合金均由单一的α相组合而成;SEM和TEM分析发现,4种高温钛合金样品均由板条α相组成,随着Sn含量的增加,α板条的宽度从0.3μm左右逐渐增加到0.6μm左右;力学性能分析发现,随着Sn含量的增加,高温钛合金的屈服强度呈现逐渐上升的趋势,抗拉强度呈现先上升后下降的趋势,延伸率呈现逐渐下降的趋势。当Sn含量为8%(质量分数)时,高温钛合金的屈服强度、抗拉强度和延伸率分别为1466.74,1560.38 MPa,0.68%。

多相Mo-Si-B合金材料的制备与微观结构

多相Mo-Si-B合金具有高熔点,理想的抗氧化性、抗蠕变性和比较好的室温断裂韧性,是非常具有吸引力的新型高温结构材料.综述了多相Mo-Si-B合金制备和微观结构的研究进展,指出Mo-Si-B组分含量和制备工艺均影响多相Mo-Si-B合金的中微观组织组成相的种类与微观结构;论述了存在的问题和今后努力的方向.

Fe-18Cr-18Mn-C-Mo(Si)-N系相图垂直截面的热力学计算

利用Thermo-Calc软件和相关数据库对Fe-18Cr-18Mn-C-Mo(Si)-N合金系在氮气压力为100kPa下随N含量变化的变温截面进行了计算.结果发现,随着C的质量分数从0增加到0.12%时,γ相区没有发生明显的变化,但对碳化物M23C6的析出产生了显著的影响,从而改变了高氮钢奥氏体化后的析出序列.当继续添加质量分数为2%的Mo时,γ/α+γ相边界向右侧移动,不但存在碳化物M23C6还有碳化物M6C.当添加不同含量的Si时,γ相区明显缩小,而且碳化物M23C6的析出温度与成分也发生了很大的变化.Fe-18Cr-18Mn-0.09C-0.8Si-0.5N钢的奥氏体化温度及Cr2N相析出温度与该合金系的热力学计算结果符合,表明这些计算结果可为Fe-18Cr-18Mn-C-Mo(Si)-N合金系的成分设计及热处理工艺提供依据.

熔覆速度对氩弧熔覆Co-Mo-Si合金涂层组织及性能的影响

为了改善机械零件的表面性能,采用氩弧熔覆技术以不同熔覆速度在304奥氏体不锈钢表面进行Co-Mo-Si涂层的合金化处理。通过倒置金相显微镜、显微硬度计、X射线衍射仪、扫描电镜、磨料磨损试验、电化学工作站分别测试了熔覆速度对合金涂层的显微组织、显微硬度、相结构及涂层的耐磨性、耐蚀性的影响。结果表明:采用氩弧熔覆技术可以在304奥氏体不锈钢表面上获得与基体结合良好、组织细密且具有较高硬度和耐蚀性的Co-Mo-Si合金涂层;当熔覆速度为160 mm/min时,Co-Mo-Si合金涂层组织均匀,硬度最大,耐磨性及耐蚀性最佳。