Joint properties of dissimilar Al6061-T6 aluminum alloy/Ti–6%Al–4%V titanium alloy by gas tungsten arc welding assisted hybrid friction stir welding

Hybrid friction stir butt welding of Al6061-T6 aluminum alloy plate to Ti–6%Al–4%V titanium alloy plate with satisfactory acceptable joint strength was successfully achieved using preceding gas tungsten arc welding (GTAW) preheating heat source of the Ti alloy plate surface. Hybrid friction stir welding (HFSW) joints were welded completely without any unwelded zone resulting from smooth material flow by equally distributed temperature both in Al alloy side and Ti alloy side using GTAW assistance for preheating the Ti alloy plate unlike friction stir welding (FSW) joints. The ultimate tensile strength was approximately 91% in HFSW welds by that of the Al alloy base metal, which was 24% higher than that of FSW welds without GTAW under same welding condition. Notably, it was found that elongation in HFSW welds increased significantly compared with that of FSW welds, which resulted in improved joint strength. The ductile fracture was the main fracture mode in tensile test of HFSW welds.     

Surface treatment of new type aluminum lithium alloy and fatigue crack behaviors of this alloy plate bonded with Ti–6Al–4V alloy strap

Samples consisting of new aluminum lithium alloy (Al–Li alloy) plate developed by the Aluminum Company of America and Ti–6Al–4V alloy (Ti alloy) plate were investigated. Plate of 400 mm × 140 mm × 2 mm with single edge notch was anodized in phosphoric solution and Ti alloy plate of 200 mm × 20 (40) mm × 2 mm was anodized in alkali solution. Patterns of two alloys were studied at original/anodized condition. And then, aluminum alloy and Ti alloy plates were assembled into a sample with FM 94 film adhesive. Fatigue crack behaviors of the sample were investigated under condition of nominal stress σ = 36 MPa and 54 MPa, stress ratio of 0.1. Testing results show that anodization treatment modifies alloys surface topography. Ti alloy bonding to Al–Li alloy plate effectively retards crack growth than that of Al–Li alloy plate. Fatigue life of sample bonded with Ti alloy strap improves about 62.5% than that of non-strap plate.     

FeCrMnNiTix高熵合金在NaCl溶液中的腐蚀行为研究

将Fe,Cr,Mn,Ni和Ti 5种金属纳米粉体经行星式球磨机混合后,采用真空熔铸法制备FeCrMnNiTi,FeCrMnNiTi_0.5,FeCrMnNi 3种高熵合金。为研究这3种合金在NaCl溶液中的腐蚀行为,运用电化学工作站测定3种合金在质量分数为3.5%的NaCl溶液中的开路电位、极化曲线和交流阻抗,利用金相显微镜和扫描电镜对腐蚀后的合金进行微观组织观察。电化学测试结果表明:当FeCrMnNiTi合金的自腐蚀电位为-0.301 V时,FeCrMnNiTi_0.5合金的自腐蚀电位为-0.443 V;腐蚀产物形貌观察表明:FeCrMnNiTi_0.5以晶界腐蚀为主,另外2种合金以点蚀为主。由此得出结论:FeCrMnNiTi耐蚀性最好,FeCrMnNiTi_0.5耐蚀性最差;加入Ti可能造成了合金晶格畸变。     

船用钛合金及钛合金粉末冶金技术

本文介绍了钛合金在舰船行业的应用现状和钛合金的几种制备方法,并重点介绍了钛合金粉末冶金技术及钛合金粉末冶金工艺现阶段面临的主要困难。     

Equation of state measurements of materials using a three-stage gun to impact velocities of 11 km/s

Results of an experimental series performed utilizing a three-stage gun to obtain precise material property equation of state (EOS) data for a titanium alloy (Ti6-Al-4V) at extreme pressure states that are not currently attainable using conventional two-stage light-gas gun technology is reported herein. What is new is the technique being implemented for use at engagement velocities exceeding 11 km/s. Shock-velocity in the target is being determined using 100 μm diameter fiber-optic pins and measuring shock transit times over a known distance between two parallel planes. These fiber-optic pins also indicate that the flyer-plate bow and tilt is comparable to two-stage light-gas gun technology. The thermodynamic state of the flyer plate prior to impact has also been determined both experimentally and calculationally. In particular, the temperature, and hence the density of the flyer-plate is also well known prior to impact. Results of these studies indicate that accurate Hugoniot information can be obtained using the three-stage light gas gun. This new test-methodology has extended the EOS of Ti6-Al-4V titanium alloy to stresses up to approximately 250 GPa.     

Formation of a crack-free joint between Ti alloyand Al alloy by using a high-power CO2 laser

The present paper aims at producing a crack-free weld between a commercially available Ti alloy (Ti-6 wt% Al-4 wt% V) and a wrought Al alloy (Al-1 wt% Mg-0.9 wt% Si). Ti alloy and Al alloy with a plate thickness of 3 mm are butt welded using a 2.5 kW continuous CO2 laser. The laser power, welding speeds and offset of the laser with respect to the joint are considered as the variable parameters. It is observed that intermetallic compounds (mainly TiAl and Ti3Al) are formed in the fusion zone depending on the amount of Al and Ti melted by the laser. These intermetallic phases are very brittle and the solid-state cracks are formed near the Al side of the interface because of the stress developed after the solidification. The formation of cracks is sensitive to the total Al content in the fusion zone. In order to minimize the dissolution of Al in the fusion zone and to increase the toughness of the intermetallic phases, Nb foil is added as a buffer between the Ti alloy and Al alloy workpieces. It is observed that the partially melted Nb acts as a barrier to dissolve Al in the fusion zone and facilitates a good joining condition for welding of Ti alloy with Al alloy. This revised version was published online in November 2006 with corrections to the Cover Date.     

Influence of Ti content on microstructure,mechanical properties and castability of directionally solidified superalloy DZ125L

Directionally solidified DZ125L alloys of various Ti content were developed by low segregation technology. The microstructure, mechanical properties and castability of directionally solidified superalloy DZ125L were investigated. With decreasing Ti content in DZ125L alloy, the size, volume fraction and separation temperature of γ′ decreased. While the tensile strength and rupture life of directional solidified cylindrical samples is also obviously decreased. Lowering Ti content in alloy resulted in free hot cracking casting blades. Compared with IN792 alloy, DZ125L alloy needs much lower Ti/Ta ratio to achieve good castability.     

Welding-Induced Angular Distortion of a 6 MM-Thick 5A06 Aluminum Alloy Plate: A Numerical Simulation

Strength of Materials - In this paper, the numerical simulation of the temperature field and welding angular distortion of a 6mm-thick 5A06 aluminum alloy plate was performed by application of the...     

生产工艺对爆炸复合用钛板的影响研究

对比热轧和卷轧工艺技术,研究了不同生产方式对爆炸复合用钛板性能和组织的影响。结果表明:块式热轧生产钛板的效果最好,炉卷轧制方式次之,但其生产率和成品率高;少量添加回收料可批量生产合格的钛板,但伸长率的富裕量降低。因此,需要严格控制原料成分,并选择适宜的生产工艺方式,以确保钛板性能满足爆炸复合要求。      

锌铜钛合金的研究进展与应用

简述了锌资源概况、锌合金的研究历程和以锌代铜的可行性,主要介绍了锌基抗蠕变合金——锌铜钛合金的使用状况及优点,特别是锌铜钛板材的情况。综述了国内外锌铜钛合金的研究和应用进展,论述了铜、钛及各合金元素在锌基合金中的作用,并阐明成分优化、形变热处理对其组织演变和性能方面的影响,最后对锌铜钛合金的应用和前景进行了探讨和展望。     

Titanium Technology in the USA-an Overview

The state of Ti research, development and industry is reviewed in this article. The fifty-year anniversary of Ti technology commercialization in the USA provides an opportunity for a historical perspective. Incorporation of “information-age“ tools into alloy development, processing, and production invigorates the technology. Consolidation, diversification and globalization have been transforming the Ti industry in the recent years.     

Mechanical properties of additive laser-welded NiTi alloy

Laser welding would be a suitable joining technique for NiTi shape memory alloy if the mechanical properties of laser weld were improved. With this purpose, effects of additive on mechanical properties of laser-welded NiTi alloy have been experimentally studied. Welding specimens used in this study were 2 mm thick hot-rolled plates with a chemical composition of Ni50.9Ti49.1. (Ni50.9Ti49.1)-Ce2 (at.%) alloy foil or Ni47Ti44Nb9 plate was used as filler metal to add Ce or Nb element into NiTi laser weld metal. Both tensile strength and the toughness of additive-welding specimens were improved significantly compared with non-additive-welding specimen. The mechanical property improvement was attributed to the fine solidification NiTi grains and good grain-linking in weld center. The microstructure control mechanisms of these two additive welds were discussed.     

钛合金表面加弧辉光离子渗镍铬及其性能研究

采用加弧辉光离子渗金属新技术处理钛合金Ti5Al2.5Sn表面,研究了渗层的相组成特点,成分分布情况,评价了改性层的磨擦摩损性能,及与钛合金基体间的接触腐蚀相容性等。结果表明加弧辉光离子渗技术可以快速地在钛合金表面获得NiCr镀渗复合层。渗层由Ni3Ti等金属间化合物组成,其硬度、耐磨性能均高于离子注氮层,具有较高的抗含Cl^-1水溶液腐蚀性能,在含Cl^-1腐蚀环境中与钛合金基体接触相容。     

钛-铝异种合金电子束焊接接头组织与性能研究

采用电子束焊接方法对厚度为2.5 mm的Ti6321钛合金板材和5083铝合金板材进行了对接焊接试验,并进行了力学性能、显微组织测试。结果表明,焊缝的钛侧及其热影响区组织主要是α'相和原始α相混合形成的马氏体组织,铝侧主要为粗大柱状晶组织,钛铝焊缝交界处析出少量Ti Al金属间化合物;焊接接头的拉伸强度约为219 MPa,接头断裂位置主要在铝侧焊缝位置,部分在钛铝两侧焊缝交界处的Ti-Al金属间化合物上。     

Characteristics of dissimilar laser-brazed joints of isotropic graphite to WC–Co alloy

The effect of Ti serving as an activator in a eutectic Ag–Cu alloy filler metal in dissimilar laser-brazed joints of isotropic graphite and a WC–Co alloy on the joint strength and the interface structure of the joint is investigated in this study. To evaluate the joint characteristics, the Ti content in the filler metal was increased from 0 to 2.8 mass%. The laser brazing was carried out by irradiating a laser beam selectively on the WC–Co alloy plate in Ar atmosphere. The threshold content of Ti required to join isotropic graphite to WC–Co alloy was 0.4 mass%. The shear strength at the brazed joint increased rapidly with increasing Ti content up to 1.7 mass%, and a higher Ti content was found to be likely to saturate the shear strength to a constant value of about 14 MPa. The isotropic graphite blocks also fractured at this content. The concentration of Ti observed at the interface between isotropic graphite and the filler metal indicates the formation of an intermetallic layer of TiC.     

AlN陶瓷的Ti-Ag-Cu活性封接工艺

在AlN陶瓷的Ti Ag Cu活性封接工艺中 ,研究Ti的引入方式对其与金属封接抗拉强度的影响。其中Ti以四种不同方式引入 :涂Ti粉、夹Ti箔、直接使用Ti Ag Cu合金焊料以及溅射Ti膜     

3D打印医用钛合金的抗菌性能和体外生物相容性

应用选择性激光熔融技术(SLM)制备出3D打印医用钛合金Ti-6Al-4V和Ti-6Al-4V-5Cu,用平板共培养法研究测定其抗菌性能,用CCK8细胞增殖测定法、鬼笔环肽细胞骨架染色法和Annexin-V/PI流式细胞术研究了这种合金的抗菌性能和对小鼠胚胎成骨前体细胞(MC3T3-E1)的体外生物相容性影响。结果表明,3D打印Ti-6Al-4V-5Cu合金具有较高的抗菌性能,对金黄色葡萄球菌的抗菌率达到(57.03±1.55)%。在CCK8细胞增殖毒性测定、细胞骨架鬼笔环肽染色实验和Annexin-V/PI双标记法流式分析三种研究中Ti-6Al-4V-5Cu表现的优越,具有更好的体外生物相容性。     

凝胶注模成形Ti6Al4V钛合金的组织和性能研究

目的 为了实现低成本、低能耗、高效率制备大尺寸复杂形状钛合金的问题,以凝胶注模技术为成形手段,制备近净成形Ti6Al4V合金,并研究其组织及性能.方法 通过溶液包覆法,在Ti6Al4V钛合金球形粉末表面包覆石蜡(PW),分析有机包覆层在凝胶注模过程中的作用机制及流变行为的影响,测定包覆前后不同粉末进行凝胶注模烧结后的组织及性能,得到该方法 对减少钛合金凝胶注模的碳氧残留的效果并进行原理分析.结果 经质量分数为0.36％的石蜡包覆后,烧结样品中碳的质量分数从0.5433％下降到0.2841％,氧的质量分数从0.3859％下降到0.3178％;烧结样品的相对密度从93.6％提高到97.5％.此外,烧结后的试样也具有较好的综合力学性能,抗拉强度为1129 MPa,屈服强度为1015 MPa,伸长率为5.18％.结论 凝胶注模成形技术在制造低成本、形状复杂、性能优异的钛合金零件方面具有良好的应用前景.     

Ti6321合金板材织构及力学性能研究

应用EBSD技术研究了Ti6321合金板材的织构特征,并对其力学性能进行了实验分析。结果表明:退火态的Ti6321合金板材横向屈服强度和抗拉强度均略高于轧向的,但塑性和冲击韧性略低于轧向的。该24mm厚退火态Ti6321合金板材织构的主要组分为{0111}2110、{2120}3412和{2021}3414,织构是造成板材力学性能各向异性的主要原因。     

铝合金船舶的腐蚀防护技术现状与展望

针对国内外铝合金船舶的船体、空舱、海水管路系统、艉板法兰等部位的铝合金腐蚀现状进行了调研分析,发现船体基本采用涂料+铝合金牺牲阳极的方法进行保护,效果良好;而空舱、海水管路系统和艉板法兰等部位,却因防腐措施不到位分别存在一定的腐蚀问题。文章结合青岛海洋腐蚀研究所多年积累的铝合金实海腐蚀研究资料,在对相应部位腐蚀问题客观分析的基础上,分别对铝合金船舶的牺牲阳极阴极保护、防腐防污涂层保护、微弧氧化处理和电绝缘保护等腐蚀防护技术,在使用过程中存在的问题以及相应应对措施进行了分析总结,同时对铝合金船舶各项腐蚀防护技术的发展前景以及需要解决的问题进行了展望。