共查询到19条相似文献,搜索用时 78 毫秒
1.
胶接对Al-Li-S4铝合金织构的影响 总被引:1,自引:0,他引:1
将新一代Al-Li-S-4铝锂合金用砂纸打磨,用磷酸进行阳极化处理,用环氧320/322胶胶接,然后以12℃/min的速率升温至120℃,保温固化1 h。采用BrukerD8 Discover型X射线衍射仪测定胶接固化后的织构,并与未胶接的Al-Li-S-4合金进行比较。结果表明:胶接后合金主要织构的成分没有发生大的变化,但在胶接应力的作用下织构的位置发生变化。其中,黄铜织构与铜织构较稳定,而立方织构的取向密度变化较大,位置也有所改变。通过研究胶接对材料织构的影响,了解材料内部应力及晶粒取向上的变化,为胶接工艺的制定及改进提供参考。 相似文献
2.
在快锻液压机上对Ti-6Al-4V合金进行了锻造变形,采用扫描电镜、背散射电子衍射技术以及X射线衍射技术研究了不同锻造方式下合金组织及晶粒取向的变化规律.在单向镦拔和换向镦拔两种不同锻造方式下,难变形区、小变形区及大变形区中α相及β相的分布差别不大,组织均匀性基本一致,两种变形方式下锻坯不同区域的应变稍有差别.进一步对不同变形区域形变织构的定量分析可知:在应变较小的边缘区域,变形主要以{0001}基面滑移为主,形成基面织构;在应变较大的内部区域,织构明显转向{11相似文献
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4.
近年来,复合材料以其优异的结构强度和性能在新一代飞机上显示出巨大的应用前景。然而,碳纤维复合材料在与金属铝接触时易发生接触腐蚀,并向金属内部扩散。而金属钛表面可以迅速生成纳米级氧化层,并且即使该氧化层受到破坏,在有氧或水的情况下又可以重新生成新的氧化层,从而避免在与碳纤维复合材料接触时被腐蚀。由于复合材料具有较高的缺口敏感度,因此,碳纤维复合材料 相似文献
5.
水基凝胶注Ti-6Al-4V合金坯体 总被引:1,自引:0,他引:1
将凝胶注模工艺应用于金属Ti6Al4V合金粉末的成形,研究了高固相含量的Ti6Al4V合金粉末的料浆的制备,比较了金属浆料与陶瓷浆料的不同。结果表明粉末的颗粒形状是影响浆料固相含量的重要因素,浆料的固相含量随分散剂的增加而增加。最后制备出了固相含量为54%(体积分数,下同)的钛合金粉末浆料和形状复杂的坯体。坯体的抗弯强度随气雾化(GA)Ti6Al4V含量增加先增大后减小,随着坯体的固相含量增大而减小。当GA-Ti6Al4V含量为80%,固相含量为50%时生坯抗弯强度最大,为18.5 MPa。 相似文献
6.
Ti-6Al-4V合金是用途最广泛的钛合金,在航空、汽车、能源、舰船、化工、医疗器械及体育用品等所有应用领域中,该合金占到50%以上。在航空业中,Ti-6Al-4V合金用作重要的零部件,从隔板、机翼、机架到压气机盘、发动机、叶片、气瓶。例如,Ti-6Al-4V在美国F22“猛禽”战斗机总重中占36%。因此,对Ti-6Al-4V零部件进行设计并改进热加工工艺有助于大大降低成本。1 Ti-6Al-4V合金的级别Ti-6Al-4V合金根据间隙元素含量被划分成两种级别,它们之间的主要差异是氧含量不同。工业级Ti-6Al-4V中氧的质量分数为0.16%~0.20%;超低间隙(ELI)… 相似文献
7.
本文研究了明Ti-6Al-4V合金在510℃下不同时间时效后组织及硬度变化。结果发现该合金在940℃固溶、510℃时效时,先从亚稳定β相中析出近等轴状的α相;延长时效时间,α相向片状生长,形成α集团,在集团内片状α的取向趋于一致,而集团间的取向不一致,这导致合金的硬度增加;继续增加时效时间,发生马氏体的分解,片状α相向等轴状转变,合金硬度降低。538℃时效时,硬度比510℃时高。采用多弧离子镀在Ti-6Al-4V合金表面形成了一层很薄且致密的(Ti,Al)N层,镀层可提高合金的显微硬度。 相似文献
8.
钛和钛合金具有高比强度和较高的刚度,广泛应用在航空领域。其中,Ti-6Al-4V合金的应用最为广泛。然而铸态下的β晶粒较大(约为2.5 mm),不利于改善合金的机械性能。为了提高合金的性能,通常采用热机械处理来获取较小晶粒,需要较高的 相似文献
9.
钛及钛合金因比强度高、耐腐蚀、生物相容性好等特点被广泛应用于航空航天、生物医疗等领域。电子束选区熔化技术(Selective electron beam melting,SEBM)是近年来发展起来的一种粉末床熔融增材制造技术,具有能量密度高、生产效率快、成形应力低、真空环境下洁净度高等特点,利用该方法制备出的钛及钛合金成为学术界及工程界的研究热点。本文综述了国内外电子束选区熔化技术制备Ti-6Al-4V合金的研究进展,重点从缺陷、显微组织及力学性能进行了分析,最后对电子束选区熔化技术的发展及应用进行了展望。 相似文献
10.
以4种不同粒径的球形Ti-6Al-4V粉末为原料,采用真空热压法进行成形固结。利用X射线衍射仪(XRD)、金相显微镜、扫描电镜、万能材料试验机分别分析粉末Ti-6Al-4V合金的物相组成、微观组织、断口形貌以及力学性能,研究粉末粒度及其组成对烧结体微观组织和力学性能的影响。研究结果表明:热压烧结Ti-6Al-4V样品致密度均可达到98%以上。不同粒度粉末烧结后的合金均为网篮排列层片状组织。合金塑性主要受原始粉末粒度影响,随原始粉末粒度增大,烧结样品的晶粒尺寸增大,从而导致合金的塑性降低。粉末粗细搭配相比于原始粗粉,有助于提高合金的塑性,从而有效降低粉末钛合金的成本。 相似文献
11.
The alloy Ti-6-Al-4V deforms superplastically in the temperature range 750 to 950° The most important factor which is responsible
for superplastic behavior was found to be the very fine grain size. Strain rate has no direct effect on superplasticity, however
when the strain rate is very low (approximately 2 × 10 s), prolonged exposure to high temperature causes grain growth and
early failure. The strain rate sensitivity factorm = 0.5 and the apparent activation energyAH = 45,000 cal/mole, which is approximately the same as the activation energy for grain boundary self diffusion of titanium.
Both values are independent of strain rate within the range 10 - 2.5 × 10 s. All the experimental points fall in a straight
line when plotted as log (εkTd*
2/DgbGb3) vs log (σ/G) with a slopen = l/m = 2. This is in excellent agreement with the theory of grain boundary sliding accommodated by dislocation motion. 相似文献
12.
J. H. Zhu P. K. Liaw J. M. Corum H. E. McCoy Jr. 《Metallurgical and Materials Transactions A》1999,30(6):1569-1578
Mechanical behaviors at 538 °C, including tensile and creep properties, were investigated for both the Ti-6Al-4V alloy and
the Ti-6Al-4V composite reinforced with 10 wt pct TiC particulates fabricated by cold and hot isostatic pressing (CHIP). It
was shown that the yield strength (YS) and ultimate tensile strength (UTS) of the composite were greater than those of the
matrix alloy at the strain rates ranging from approximately 10−5 to 10−3 s−1. However, the elongation of the composite material was substantially lower than that of the matrix alloy. The creep resistance
of the composite was superior to that of the matrix alloy. The data of minimum creep strain rate vs applied stress for the composite can be fit to a power-law equation, and the stress exponent values of 5 and 8 were obtained
for applied stress ranges of 103 to 232 MPa and 232 to 379 MPa, respectively. The damage mechanisms were different for the
matrix alloy and the composite, as demonstrated by the scanning electron microscopy (SEM) observation of fracture surfaces
and the optical microscopy examination of the regions adjacent to the fracture surface. The tensile-tested matrix alloy showed
dimpled fracture, while the creep-tested matrix alloy exhibited preferentially interlath and intercolony cracking. The failure
of the tensile-tested and creep-tested composite material was controlled by the cleavage failure of the particulates, which
was followed by the ductile fracture of the matrix. 相似文献
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14.
Influence of texture on fatigue properties of Ti-6Al-4V 总被引:1,自引:0,他引:1
Tensile properties, high cycle fatigue strength, and fatigue crack propagation behavior were evaluated on highly textured
Ti-6Al-4V material to investigate the influence of a preferred crystallographic orientation on mechanical properties. Thermomechanical
treatments were used to develop three different textures: a basal, basal/transverse, and transverse type, all of which exhibited
the same homogeneously equiaxed microstructure. The Young’s modulus was found to vary between 107 and 126 GNm-2, and yield strength changed from 1055 to 1170 MNm-2. Ductility was only slightly affected by texture. High cycle fatigue and fatigue crack growth measurements were performed
in vacuum, laboratory air, and a 3.5 pct NaCl solution. It is shown that laboratory air can be regarded as a quite corrosive
environment. In vacuum the highest fatigue strength values were measured whenever loads were perpendicular to basal planes.
However, these conditions had the highest susceptibilities to air and 3.5 pct NaCl solution environments. Nearly no influence
of texture on fatigue crack propagation was found in vacuum, but in a corrosive environment crack growth parallel to (0002)-planes
was much faster than perpendicular to these planes. To explain the corrosive effect on the fatigue properties of the textured
material hydrogen is thought to play a key role. 相似文献
15.
M.?D.?S.?Pirzada F.?H.? Froes S.?N.?Patankar 《Metallurgical and Materials Transactions A》2004,35(6):1899-1903
Synthesis of nanocrystalline Ti-6Al-4V was explored using mechanochemical processing. The reaction mixture was comprised of
CaH2, Mg powder, anhydrous AlCl3, anhydrous VCl3, and TiCl4. The milled powder (reaction product) primarily consisted of nanocrystalline alloy hydride having a composition (Ti-6Al-4V)H1.942, along with MgCl2 and CaCl2 as by-products. Aqueous solutions of nitric acid, sulfuric acid, and 1 pct sodium sulfite were found to be very effective
in leaching of the chlorides from the milled powder. The (Ti-6Al-4V)H1.942 on dehydrogenation at 375°C resulted in nanocrystalline Ti-6Al-4V alloy powder. 相似文献
16.
利用扫描电镜和背散射衍射技术研究了Ti-6Al-4V合金在不同锤锻变形方式下的组织与取向变化.结果显示:随着镦拔变形次数的增加,Ti-6Al-4V合金中α相及β相组织均趋于均匀,而且两相的取向聚集越不明显;进一步热处理后,锻造过程中形变储存能得到释放,在释放过程中两相也会发生一定的倾转,轴向三次镦拔或者换向三次镦拔对组织均匀性改善明显.综合分析发现,密排六方结构的α相的取向分布对变形方式较敏感:原始棒材以及一次镦拔时,合金中α相的取向{0001}基面织构占了很大部分;随着镦拔次数增多,形变能增加,虽然{0001}基面滑移被抑制,但是{10相似文献
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G. P. Grabovetskaya O. V. Zabudchenko E. N. Stepanova 《Russian Metallurgy (Metally)》2010,(3):229-234
The effect of alloying with 0.002–0.24 wt % H on the creep of the Ti-6Al-4V alloy at a temperature of ∼0.15T
m
(T
m
is the melting temperature) is studied. The formation of a submicrocrystalline structure in the alloy is found to increase
the stress-rupture strength and the hydrogen embrittlement resistance. Possible causes of the increase in the deformation
localization resistance of the alloy in the presence of hydrogen in a solid solution are discussed. 相似文献
19.
S. S. Satheesh Kumar S. Sathiyanarayanan A. Sambasiva Rao T. Raghu 《Transactions of the Indian Institute of Metals》2009,62(2):129-133
Low density, excellent corrosion resistance, moderate strengths at high temperatures make titanium based alloys candidate
materials for advanced aerospace structures. Advanced joining techniques are emulating for fabrication of complex aerospace
structures. Roll bonding is one such solid state joining technique where bonding between two rough and clean surfaces is obtained
under high temperature and pressure. The work horse dual phase titanium alloy Ti-6Al-4V finds extensive structural application
in aerospace and space industries. In the present study, two Ti-6Al-4V sheets are stacked together and encapsulated in a mild
steel can followed by evacuation and hot crimping. The pack is extensively deformed to ∼84% reduction in thickness employing
conventional hot rolling mill. Partially roll bonded 0.74mm thick sheets were obtained and microstructural evolution was studied
using light microscopy and scanning electron microscopy. The incompletely bonded interface was analyzed through elemental
mappings by Electron Probe Micro Analyzer and compared with completely bonded region. The partially bonded region revealed
the presence of aluminium oxide at the interface which possibly could have hindered complete bonding at that region. The room
temperature tensile properties of as- roll bonded Ti-6Al-4V nearly approaches the base material properties. 相似文献