Structure and tribological properties of modified layer on 2024 aluminum alloy by plasma-based ion implantation with nitrogen/titanium/carbon

1　INTRODUCTIONGoodmachinability ,lowdensityandhighspecif icstrengthmakealuminumanditsalloysextensivelybeusedinmanyindustries ,especiallyinaviationandspaceflightindustry .Howeverlowsurfacehardnessandlowwearresistanceoftenlimittheirengineeringapplications .Nitrogenionimplantationintoalu minumanditsalloysoffersthepossibilityofapplica tionswherebothhighwearresistanceandlowdensityarerequired[15] .Moreover ,ourpreviousinvestiga tion[6 ,7] presentedthatwhenaluminumalloywasim plantedwithnitrogen…     

铝合金表面氮和钛等离子体基离子注入改性层XPS研究

用XPS(X射线光电子能谱 )和GXRD(小掠射角X射线衍射 )研究了铝合金等离子体基离子注入氮再注入钛最后复合注入氮和钛改性层的成分分布及相结构 ,并用Gaussian Lorentzion峰位拟合方法分析了改性层中不同深度处各元素的化学态及其在相结构中的分布。结果表明 ,复合改性层的表层有较高浓度的氮和钛 ,次表层有较高浓度的钛及一定浓度的氮 ,铝 /钛界面有较宽的过渡区 ,基体中氮呈高斯分布。改性层主要由TiN ,TiO2 ,α Ti,TiAl3 ,Al2 O3 和AlN等组成 ,氮和氧还以固溶态的形式存在。最表层含有大量TiN及部分TiO2 ;次表层含有大量α Ti及许多TiN ;过渡层由TiO2 ,TiN ,TiAl3 ,Al2 O3 和AlN等组成 ;注氮层包括AlN ,Al2 O3 及α(Al)。各元素在相应相结构中的浓度分布与其成分深度分布基本相似。     

Wear and corrosion properties of plasma-based low-energy nitrogen ion implanted titanium

Plasma-based low-energy nitrogen ion implantation, including plasma source ion nitriding/carburizing and plasma source low-energy ion enhanced deposition, has emerged as a low-temperature surface engineering technique for metal and alloy. In this paper, the pure metal Ti samples have been modified by the plasma source ion nitriding process at a process temperature of 700 °C for a processing time of 4 h. The nitrided Ti surfaces were constructed of a continuous and dense Ti₂N compound layer about 2 μm thick and a 7-8 μm diffused layer. During tribological test on a ball on disk tribometer against the Si₃N₄ ceramic counterface, a low friction coefficient of about 0.3 and the faint wear volume were obtained for the nitrided Ti samples. The cyclic polarization curves of the nitrided Ti samples in 3.5% and 6.0% NaCl solutions showed that the improved pitting corrosion resistance with an increase of corrosion potential and a decrease of passive current, compared with that of the unnitrided Ti sample. The plasma source ion nitriding of the Ti samples provided the engineering surfaces for the functional applications with the combined improvement in wear and corrosion resistance.     

Improvement of tribological behavior of a Ti-Al-V alloy by nitrogen ion implantation

The tribological properties especially wear and hardness of a Ti-Al-V alloy with nitrogen implantation (energy 60 keV) were investigated. The implantation was carried out at fluences range from 1×1016 to 4×1017 ions/cm2. Glancing angle X-ray diffraction (GAXRD) and X-ray photoelectron spectroscopy (XPS) analyses were performed to obtain surface characterization of the implanted sample. The unimplanted and implanted samples were also annealed at 600 ℃ in order to understand the influence of annealing on the tribological properties of Ti-Al-V. The hardness shows significant improvement at the higher fluence. After annealing at 600 ℃, the friction coefficient exhibits a relative decrease for the nitrogen-implanted samples. In addition, the wear rates of the implanted samples exhibits a great decrease after annealing at 600 ℃. Nature of the surface and reason for the variation and improvement in wear resistance were discussed in detail.     

铝合金等离子体基离子注入氮／钛层的结构

用X射线光电子能谱（XPS）和小掠射角X射线衍射（GXRD）研究了铝合LY12等离子体基离子注入氮／钛改性层的结构。结果表明。氮在注入层呈高斯分布,而钛沿注入方向逐渐减少。钛的注入对已注入的氮的分布有重要影响。钛的等离子体密度直接影响钛在改性层中的成分、相结构。改性层主要由TiO2,Al2O3,Aln,TiAl3,TiN或Ti组成。     

Microstructure characteristics and mechanical properties of rheoformed wrought aluminum alloy 2024

The microstructure characteristics and mechanical properties of 2024 wrought aluminum alloy produced by a new rheoforming technique under as-cast and optimized heat treatment conditions were investigated. The present rheoforming combined the independently developed rheocasting process, named as LSPSF (low superheat pouring with a shear field) process, and the existing squeeze casting process. The experimental results show that LSPSF can be used to prepare sound semi-solid slurry within 25s to fully meet the production rate of squeeze casting. The primary α (Al) presents in mean equivalent diameter of 69μm and shape factor of 0.76, and features zero-entrapped eutectics. Compared with conventional squeeze casting, the present LSPSF rheoforming can improve the microstructures and mechanical properties. An optimized heat treatment results in substantial reduction of microsegregation and significant improvement of mechanical properties, such as yield strength of 321MPa, ultimate tensile strength of 428MPa and elongation of 12%.     

超塑预处理对2024铝合金组织和性能的影响

采用三种工艺研究了超塑预处理对2024铝合组织和性能的影响.拉伸试验结果表明:超塑预处理后合金的力学性能明显提高,抗拉强度均在572 N/mm2以上,最高达到580 N/mm2,相应的伸长率也在9.1%以上.比2024铝合金的T62状态的抗拉强度(440 N/mm2)和伸长率(5%)分别提高32%和80%.但时效时间不少于60 min,合金的力学性能急剧降低.     

Friction and wear properties of UHMWPE against ion implanted titanium alloy

In this study, a new two-step plasma immersion ion implantation technique was developed and applied for the modification of Ti6Al4V alloy; firstly ion implanting with nitrogen at high temperature and followed with oxygen in high dose. A graded titanium oxide-titanium nitride film was obtained on the surface of the Ti6Al4V alloy. The contact angle and the microhardness of the modified alloys were measured. The friction and wear properties of UHMWPE rubbing against the modified alloys under lubrication of distilled water were investigated using a pin-on-disc tribometer. The wettability and the microhardness of the alloy surfaces were found to be increased significantly after ion implantation. The friction coefficient decreased by nearly 5 times and the wear resistance of UHMWPE increased by about 40 times against the ion implanted Ti6Al4V alloy. Many deep furrows were found on the surface of the un-implanted alloy and were absent in the ion implanted surfaces of the alloy.     

ZL109铝合金表面多弧离子镀TiN薄膜的制备及性能

利用正交设计试验探讨了基体温度、偏压、溅射时间、沉积时间对ZL109表面沉积TiN涂层时,对薄膜显微硬度和膜/基结合力的影响.结果表明,在ZL109表面多弧离子镀制备TiN薄膜的最佳工艺为:基体温度260 ℃、偏压200 V、沉积时间30 min、溅射时间8 min、Ti靶电流80 A、炉内总压1 Pa(Ar和N_2流量比为1∶2).在此工艺下制备的TiN薄膜显微硬度达到1500 HV0.05,膜/基结合力达到36 N,膜厚约2～3 μm.     

Tribological behavior of different films on Ti-6Al-4V alloy prepared by plasma-based ion implantation

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时效时间对冷轧2024铝合金组织和力学性能的影响

通过拉伸力学性能及硬度测试和透射电子显微镜（TEM）观察,研究了室温条件下30%变形量冷轧2024铝合金180 ℃时效不同时间的力学性能和组织。结果表明,冷轧态2024铝合金在180 ℃时效时,出现了双峰时效强化。时效120 min时,合金中含有大量位错墙,有大量S’相析出,出现第一个强化峰,合金抗拉强度为560 MPa,伸长率为3.6%;时效720 min时,合金中S’相完全溶解,有Ω相析出,且位错含量降低,出现第二个强化峰,此时合金抗拉强度（563 MPa）与第一个峰值时几乎相等,但伸长率达9%,较120 min时提升150%。     

Effect of nitrogen ion implantation dose on torsional fretting wear behavior of titanium and its alloy

Various doses of nitrogen ions were implanted into the surface of pure titanium, Ti6Al7Nb and Ti6Al4V, by plasma immersion ion implantation. Torsional fretting wear tests involving flat specimens of no-treated and treated titanium, as well as its alloys, against a ZrO₂ ball contact were performed on a torsional fretting wear test rig using a simulated physiological medium of serum solution. The treated surfaces were characterized, and the effect of implantation dose on torsional fretting behavior was discussed in detail. The results showed that the torsional fretting running and damage behavior of titanium and its alloys were strongly dependent on the dose of the implanted nitrogen ions and the angular displacement amplitude. The torsional fretting running boundary moved to smaller angular displacement amplitude, and the central light damage zone decreased, as the ion dose increased. The wear mechanisms of titanium and its alloys were oxidative wear, abrasive wear and delamination, with abrasive wear as the most common mechanism of the ion implantation layers.     

Friction and wear properties of N+ ion implanted nylon 1010

The PA1010 was implanted with 450 keV N ions to three doses of 5× 1014 cm-2 , 2.5× 1015 cm-2 and 1.25 × 1016 cm-2. The friction and wear behaviors of the ion implanted PA1010 disks rubbing with two ceramic (ZrO2 and Si3N4) balls were studied using a pin-on-disk tribometer under dry friction. The results shows that the wear resistance of PA1010 is increased with the increasing implantation doses. The adhesion, plastic deformation and plow groove are wearing mechanisms for un-implanted PA1010, while abrasive wear for implanted PA1010.     

Comparison of corrosion- fatigue properties of precorroded 6013 bare and 2024 bare aluminum alloy sheet materials

The corrosion- fatigue resistance of precorroded 6013 bare and 2024 bare aluminum alloy sheet materials was evaluated to compare the effect of corrosion on initiation and propagation of fatigue cracks. The specimens were precorroded in 3.5% NaCl water solution per ASTM G 44 for periods of 4 and 30 days, and then were subjected to cyclic testing to failure in a 3.5% NaCl corrosive environment. The notched 6013 specimens showed better corrosion- fatigue resistance for the longer exposure time only. In all other cases, the 2024 material had better resistance. Fractographic and microstructural examinations sug-gested that the lower corrosion- fatigue life of the 6013 alloy is due to intergranular corrosion. Although the surface corrosion (pitting) on the 2024 alloy appeared severe, there was little evidence of intergranu-lar corrosion in this alloy.     

预拉伸处理对2024铝合金组织和性能影响

采用硬度测试、室温力学性能测试、组织观测,研究了自然时效前的预拉伸(预拉伸率1%、1.5%,2%、2.5%、3%)对2024铝合金时效过程和拉伸性能影响。结果表明,预拉伸处理延缓了合金的自然时效过程,但提高了合金的硬度和强度。当预拉伸率为2%时,合金的最高强度和伸长率分别为456 N/mm2,20.6%,这是由于冷变形量不同、回复所引起的软化、GPB区和S″相强化综合作用所导致的。自然时效时,析出物为GPB区、T相(Al20Cu2Mn3)及S″相(Al2CuMg),其中GPB区、S″(Al2CuMg)相为主要强化相,T相(Al20Cu2Mn3)有细化晶粒的作用,比未预拉伸处理合金的析出相数量多,且析出相分布更均匀,使合金厚板的强度提高。     

电解生产铝钛合金研究与实践

介绍了在铝电解槽中加入含钛氧化钛直接电解生产铝钍合金的工业实践，通过调整电解工艺技术条件．使电解生产过程受到的影响降到最低程度，电解生产的铝钛合金应用于内燃机活塞与汽车轮毂,完全满足活塞与轮艇机械性能的要求。同时大幅度降低了铝钛合金制造成本。经济效益显著。并具有推广价值。     

2024铝合金浸锌工艺研究

试验研究了浸锌工艺及溶液组成对2024铝合金基体浸锌层及电镀镍层外观和结合力的影响,优化了浸锌液的组成及工艺条件.发现良好的浸锌层是提高镀层与基体结合力的关键.     

Tensile and fatigue properties of aluminum alloy sheet 6022

Tensile and fatigue tests were performed on aluminum alloy 6022 T4E29 and T6 sheet specimens in ambient air. The tensile and fatigue properties were compared with other commercial aluminum alloys. The results showed that 6022 alloy has high fatigue strength and good ductility with moderate tensile strength.     

2024/3003铝合金的高温退火研究

采用双流浇注连续铸造方法获得了在过渡层上具有宏观成分梯度分布的2024/3003铝合金.通过组织观察和力学性能测试研究了该合金高温退火后的组织和性能变化.结果表明,2024/3003铝合金经480℃高温退火后,内层合金的洛氏硬度比铸态时的大幅提高,但随退火时间的延长,硬度的增幅很小,这种硬度变化是由于合金元素在α基体中固溶强化引起的.外层合金的硬度随退火时间的延长则明显降低,这是由于基体组织发生了再结晶和晶粒长大,而合金的固溶强化效果有限;高温退火对2024/3003合金的宏观成分梯度分布影响很小.     

添加镍颗粒的铝/钛异种材料电阻焊接头力学性能及显微组织分析

使用三相次级整流电阻焊机对LY12铝合金/TC4钛合金进行电阻点焊,并在板材中间添加了镍颗粒. 结果表明,最佳工艺参数为电极压力3.03 kN,预热脉冲焊接电流7.5 kA/10 cyc(1 cyc=0.02 s),焊接脉冲焊接电流12.1 kA/45 cyc,缓冷脉冲焊接电流7.5 kA/10 cyc,接头的最大拉剪力为7.12 kN. 铝合金侧熔核的显微组织为细小的等轴晶,钛合金侧熔核的显微组织为针状马氏体,IMC层由靠近铝合金侧的一层1～2 μm厚的NiAl3和在钛合金/铝合金之间散乱分布着的TiAl3共同构成.