Identification of constitutive model parameters for nickel aluminum bronze in machining

The material of nickel aluminum bronze (NAB) presents superior properties such as high strength, excellent wear resistance and stress corrosion resistance and is extensively used for marine propellers. In order to establish the constitutive relation of NAB under high strain rate condition, a new methodology was proposed to accurately identify the constitutive parameters of Johnson?Cook model in machining, combining SHPB tests, predictive cutting force model and orthogonal cutting experiment. Firstly, SHPB tests were carried out to obtain the true stress?strain curves at various temperatures and strain rates. Then, an objective function of the predictive and experimental flow stresses was set up, which put the identified parameters of SHPB tests as the initial value, and utilized the PSO algorithm to identify the constitutive parameters of NAB in machining. Finally, the identified parameters were verified to be sufficiently accurate by comparing the values of cutting forces calculated from the predictive model and FEM simulation.

Effect of heat treatment on microstructure and properties of hot-extruded nickel-aluminum bronze

The effect of heat treatment on the microstructure and properties of a hot-extruded nickel-aluminum bronze was investigated. Experimental materials were heat treated through different processes, including quenching, normalizing, aging and annealing, and their microstructure, corrosion resistance and mechanical properties were characterized. It is found that quenching causes all β phase transformed into β′ phase, however, normalizing causes β phase transformed into β′, α and κ phases. When the quenched sample is aged, fine к phase is precipitated from the as-quenched microstructure of β′ phase. Annealing causes the transformation of β′ into α and к phases. The results of mechanical property tests show that quenching, normalizing and aging improve the tensile strength and hardness of the experimental material, with a corresponding fall in elongation. Annealing raises the elongation but reduces the tensile strength and hardness. Furthermore, corrosion resistance of nickel-aluminum bronze ranks from worse to better in the following order: aged, quenched, normalized, hot-extruded and annealed. However, with the exposure time of corrosion test increasing, the difference of average corrosion rate between those nickel-aluminum bronzes turns small.

Correlation between microstructure and corrosion and cavitation erosion behaviors of nickel aluminum bronze

The microstructure,corrosion and cavitation erosion(CE)behaviors of the as-cast and four different heat treated nickel aluminum bronzes(NABs)in 3.5 wt.%NaCl solution were investigated.The results show that after annealing,β′transformed into the eutectoid microstructure,and moreκIV precipitated fromα.Less eutectoid microstructure and moreβ′were obtained after normalizing.The quenched NAB mainly consisted ofαandβ′phases,and fine,acicularαandκphases precipitated insideβ′after subsequent aging.The largest proportion of the eutectoid microstructure,which underwent severe selective phase corrosion,was responsible for the lowest corrosion resistance of the annealed NAB.The quenched NAB possessed the most protective film and hence the highest corrosion resistance.The mechanical attack was primarily responsible for the CE damage for the as-cast,annealed and normarlized NABs.The quenched and quenched+aged NABs exhibited superior CE resistance because of the high hardness.The CE−corrosion synergy dominantly caused CE degradation,and it was largely attributed to corrosion-enhanced-CE.

Corrosion Behavior of Heat Treated Nickel-Aluminum Bronze Alloy in Artificial Seawater

The effect of microstructure of nickel-aluminum bronze alloy (NAB) on the corrosion behavior in artificial seawater is studied using linear polarization, impedance and electrochemical noise tests. The alloy was heat treated in different heating cycles including quenching, normalizing and annealing. Microstructure of the specimens was characterized before and after heat treatment by optical microscopy and scanning electron microscopy. Results showed that the value of pearlite phase in the normalized alloy is much more than other specimens, leading to higher corrosion resistance. Polarization test showed that starting point of passivation in the polarization of the normalized alloy is lower than other specimens. The dissolution of Mn and Fe rich phases increased the Mn and Fe contents in solid solution, and this enhanced the passivation power of the surface of the alloy. The effect of the alloying elements was seen by a lower corrosion potential and an inflexion at around 280 mV (SCE) in the polarization curve, indicating the preferential dissolution of some elements beyond that potential. The polarization curve showed that the anodic polarization behavior of the alloy in the solution was essentially controlled by the intermetallic phases, mainly containing Cu. Two types of corrosion, pitting and selective corrosion, were observed in the specimens after being exposed to artificial seawater.

Pyrimidine derivative as eco-friendly corrosion inhibitor for nickel−aluminum bronze in seawater

A pyrimidine derivative,6-phenyl-2-thiouracil(PT),was synthesized for developing a corrosion inhibitor(CI)applied in the protection of the nickel−aluminum bronze(NAB)in seawater.The anti-corrosion effect of PT was evaluated by the mass loss experiment,electrochemical tests and surface analysis.The results show that PT exhibits excellent inhibition performance and the maximum inhibition efficiency of PT reaches 99.6%.The interaction mechanism was investigated through X-ray photoelectron spectroscopy(XPS)and molecule dynamics simulation based on the density functional theory(DFT).The S-Cu,Al-N and Cu-N bonds are formed by the chemical interactions,leading to the adsorption of PT on the NAB surface.The diffusion of corrosive species is hindered considerably by the protective PT film with composition of(PT-Cu)_(ads)and(PT-Al)_(ads)on the PT/NAB interface.The degree of suppression is increased with the addition of more PT molecules.

Effect of microstructure on the mechanical and corrosion behaviors of a hot-extruded nickel aluminum bronze

In this paper, the influence of microstructure on the corrosion behavior of a hotextruded nickel aluminum bronze was studied. Three kinds of samples subjected to the hot-extrusion, anneMing and quenching conditions were prepared and immersion tests in 3.5% NaCl solution were carried out. Microstructures and corrosion surface morphologies of the samples were observed by SEM. It was found that the retained β＇ martensite and （α＋kiii） lamella eutectoid in the as hot-extruded material were eliminated after annealing, and corrosion resistance of the alloy was improved. As to the as-quenched material, its corrosion rate was higher than that of the as hotextruded material since the volume fraction of β＇ phase which was anodic to α phase increased after quenching. As regards the mechanical properties, the as-quenched sample possesses the highest hardness and tensile strength among the three kinds of samples, while the as-annealed sample possesses the highest elongation. That is to say, heat treatment plays different roles in the mechanical properties and corrosion resistance of the experimental alloy.

Cavitation Erosion Corrosion Behaviour of Manganese-nickel-aluminum Bronze in Comparison with Manganese-brass

The cavitation erosion corrosion behaviour of ZQMn12-8-3-2 manganese-nickel-aluminum bronze and ZHMn55- 3-1 manganese-brass was investigated by mass loss, electrochemical measurements （polarization curves and electrochemical impedance spectroscopy） and the cavitation damaged surfaces were observed by scanning electron microscopy （SEM）. The results showed that ZQMn12-8-3-2 had better cavitation erosion resistance than ZHMn55-3-1. After the cavitation erosion for 6 h, the cumulative mass loss of ZQMn12-8-3-2 was about 1/3 that of ZHMn55-3-1. The corrosion current density of ZQMn12-8-3-2 was less than that of ZHMn55-3-1 under both static and cavitaiton condition. The free-corrosion potentials of ZQMn12-8-3-2 and ZHMn55-3-1 were all shifted in positive direction under cavitation condition compared to static condition. In the total cumulative mass loss under cavitation condition, the pure erosion played a key role for the two tested materials （74% for ZHMn55-3-1 and 60% for ZQMn12-8-3-2）, and the total synergism between corrosion and erosion of ZQMn12-8-3-2 （39%） was larger than that of ZHMn55-3-1 （23%）. The high cavitation erosion resistance of ZQMn12-8-3-2 was mainly attributed to its lower stacking fault energy （SFE）, the higher microhardness and work-hardening ability as well as the favorable propagation of cavitation cracks for ZQMn12-8-3-2, i.e., parallel to the surface rather than perpendicular to the surface for ZHMn55-3-1.

电弧增材镍铝青铜的组织与性能

镍铝青铜合金由于其在海水中的高耐腐蚀性能、抗生物污染性能和良好的抗空化冲击性能,被广泛运用于船舶螺旋桨的制造,但传统的铸造镍铝青铜由于材料成本过高,并且性能已不再适用于现今越来越高的要求.为了获得性能优异的镍铝青铜构件,采用了电弧增材制造技术成功制造了镍铝青铜合金构件,研究了铸造镍铝青铜和电弧增材的镍铝青铜的微观组织和力学性能的差异.结果表明,与铸态镍铝青铜合金相比,电弧增材制造的镍铝青铜合金有更细小的微观组织,κⅠ相的析出被抑制,绝大多数的β′相转变为α+κⅢ的共析组织,元素分布更均匀.与铸态镍铝青铜相比(545 MPa,20%),电弧增材制造的镍铝青铜构件展现了更加优异的力学性能,极限抗拉强度达到700 MPa,断后伸长率达到38%.

水下搅拌摩擦加工对铸态镍铝青铜空蚀行为的影响

为了进一步提高铸态镍铝青铜抗空蚀性能,采用水下搅拌摩擦加工技术对其进行表面改性。观察并测试了加工前后材料的微观组织和力学性能,对比讨论了铸态和水下搅拌摩擦加工后镍铝青铜在蒸馏水和人工海水中的空蚀行为,分析了微观组织与空蚀机理的关系。研究结果表明,水下搅拌摩擦加工后,镍铝青铜组织细化,各相分布均匀,加工区中心平均显微硬度约为400 HV,是铸态样品的2倍。在2种介质空蚀试验中,水下搅拌摩擦加工镍铝青铜累计空蚀质量损失均较低,空蚀18 h后SFSP态NAB在蒸馏水和人工海水中的质量损失分别是2.55 mg和4.85 mg,约为铸态NAB质量损失的50%和44%,具有更好的抗空蚀性能。晶粒细化和小尺寸晶粒κ相弥散强化是提高铸态镍铝青铜的抗空蚀性能的主要原因。

增材制造镍铝青铜合金的制备与腐蚀行为研究进展

镍铝青铜合金因具有较好的延展性、强度、断裂韧性及耐腐蚀性能而广泛应用于石油和天然气泵系统、航空和船舶工业应用等领域。传统铸造工艺制备的镍铝青铜具有复杂的物相组成,在严苛的服役环境中容易发生严重的腐蚀失效。近年来,增材制造技术在铜合金加工领域获得迅猛的发展,基于快速非平衡凝固特性,能够通过显微组织调控来提高铜合金的机械性能,同时有望提升其在严苛服役环境中的耐腐蚀性能。本文列举了不同增材制造技术制备的镍铝青铜合金,围绕其显微组织、力学性能以及腐蚀行为展开深入探讨,进一步对比分析了不同制备工艺参数以及热处理工艺与镍铝青铜显微组织的关联机制及其对腐蚀行为的影响规律。本文通过构建增材制造镍铝青铜制备工艺-显微组织特征-耐腐蚀性能之间的内禀关系,能够为高性能增材制造镍铝青铜的设计优化及应用提供理论基础和实践指导。

ZCuAl9Fe4Ni4Mn2镍铝青铜的化学成分优化

研究了ZCu Al9Fe4Ni4Mn2镍铝青铜螺旋桨材料化学元素、铝当量和铁镍比对合金力学性能的影响,确定了合金的最佳成分范围。

新型镍铝青铜的电偶腐蚀行为研究

海水泵阀等附件是海水管系的重要部件 ,国内常用锡青铜、硅黄铜制造 ,与目前推广使用的B10合金在海水中偶合时 ,电偶腐蚀较重 ,不能满足海水管系对高可靠性的要求。为此 ,研制了一种与B10海水管道材料配套使用的海水泵、阀材料。通过测量研制合金及常用泵阀材料与B10、B30等管道材料偶合时的电偶电流、电偶电位和电偶腐蚀率等参量 ,研究了新研制的合金在海水中的电偶腐蚀行为。

镁合金表面激光制备镍铝青铜涂层

利用激光熔覆的方法在AZ31B镁合金表面制备镍铝青铜涂层,采用扫描电镜、X射线衍射仪和显微硬度仪对涂层的微观形貌、物相以及显微硬度进行分析,采用PS–168A型电化学测量系统对涂层以及母材进行电化学腐蚀性能测试。结果表明,涂层内白色基体上析出富Cr的玫瑰状和块状的K相,涂层的物相主要由FeAl3、Al3Ni、Ni、Cu、Cr等组成,涂层的显微硬度最高可达602 HV0.2,较母材的50 HV0.2提高了约11倍,涂层的腐蚀电位?1.02 V较母材的?1.49 V提高了0.47 V。

界面传热系数的反求计算

介绍了在镍铝青铜水玻璃砂型铸造中铸件-砂型界面传热系数的反求计算。首先对铸件、铸型的温度进行测量,然后通过ProCAST反求计算,得到了符合实际的传热系数。该方法可用于其它合金铸造过程中界面传热系数的确定。

Cu-3镍铜合金砂带磨削试验研究

分析了Cu-3镍铜合金砂带磨削加工过程中,砂带粒度和磨削用量的不同对磨削加工效率、工件表面质量和砂带磨损的影响。采用氧化铝磨料砂带在不同的砂带线速度或磨削压力下对镍铜合金进行了工艺试验,对材料去除量、工件表面粗糙度和砂带磨损量进行了测量。研究表明:增加砂带线速度和磨削压力可在一定程度上提高材料去除率和磨削比;随着磨削压力的增大,工件表面粗糙度呈增大趋势;随着砂带粒度的增大,工件表面粗糙度呈减小趋势;砂带线速度为25m/s,磨削压力为43N,砂带粒度为P240时,镍铜合金综合磨削效果最好。

镍铝青铜合金仿生表面的砂带磨削及其降噪特性

针对镍铝青铜合金材料难以加工出仿生沟槽表面从而提高其降噪性能的问题,利用金字塔砂带和空心球砂带在镍铝青铜合金材料表面上磨削出仿生沟槽,并搭建配套试验平台来对镍铝青铜合金材料表面进行仿生沟槽结构的磨削加工。提取了磨削表面的特征,据此进行流体噪声计算,对比分析了金字塔砂带磨削出的仿生表面和空心球砂带磨削出的仿生沟槽表面的噪声性能,结果显示:金字塔砂带磨削出的规则仿生沟槽表面声学能量等级的平均值为18.07 dB,空心球砂带磨削出的不规则仿生沟槽表面声学能量等级的平均值为37.6 dB。试验中,两种砂带磨削加工后的镍铝青铜合金表面均具有仿生沟槽结构,且金字塔砂带磨削出的规则仿生沟槽表面具有更好的水下降噪性能。

热处理对铸态镍铝青铜疲劳裂纹扩展速率的影响

对铸态镍铝青铜(NAB)进行了920℃正火和675℃退火热处理,研究了不同状态NAB的显微组织和拉伸性能;采用直流电压降(DCPD)法测试了其疲劳裂纹扩展速率,观察了裂纹扩展路径及疲劳断口形貌。结果表明:退火态与铸态试样的显微组织均由基体α相、残余β相以及三种Ni-Fe-Al金属间化合物相(κⅡ,κⅢ,κⅣ)组成,而正火态试样组织则由较多的残余β相以及均匀分布的κⅣ相组成,其强度更高但塑性明显降低;铸态试样的疲劳裂纹扩展速率最快,正火态试样的最慢;铸态和退火态试样中的疲劳裂纹在κ相相界处扩展,断裂方式主要为脆性解理断裂,而正火态试样的疲劳裂纹主要穿过α相扩展,断口出现了疲劳辉纹,且其疲劳裂纹扩展路径最为曲折。

温轧高强韧镍铝青铜合金的组织与力学性能

通过形变量为75%的温轧形变热处理,制备了一种超细组织的QAl10-4-4镍铝青铜合金,研究其微观组织与力学性能。结果表明:经大变形温轧后,温轧后的镍铝青铜材料由超细层状(α+β′)双相组织以及细小的k相组成(其中α相为铜基固溶体、β′相为共析相变受阻产生的Cu3Al基马氏体及NiAl析出相、k相为Fe3Al、NiAl等金属间化合物),合金的屈服强度由318 MPa提升至1020 MPa,抗拉强度由784 MPa提升至1104 MPa,具有7.8%的均匀伸长率并呈现良好的应变硬化能力。温轧镍铝青铜合金的高强度主要归因于位错强化、细晶强化以及温轧过程中诱发的纳米析出强化,而良好的塑韧性主要与超细的片层α相和β′相的应力应变协调有关。温轧形变热处理是制备高强韧镍铝青铜合金的一种有效方法。

退火工艺对ZCuAl9Fe4Ni4Mn2镍铝青铜组织与力学性能的影响

通过采用金相显微镜（OM）、扫描电镜（SEM）、常温拉伸试验等分析手段,研究了退火温度对船舶推进器用ZCuAl9Fe4Ni4Mn2镍铝青铜组织与性能的影响。研究表明：镍铝青铜铸态组织由基体α相及大小不同、形态各异的金属间化合物（Fe,Ni）Al相组成,部分（Fe,Ni）Al相较为粗大。随着退火温度的升高,组织中粗大金属间化合物逐渐减少,组织得到细化。经980℃保温2h,随炉冷却到580℃,然后出炉空冷的退火工艺,镍铝青铜抗拉强度从铸态的487MPa提高到621MPa,伸长率从16.82%提高到17.83%。

铝青铜焊接热影响区的空蚀形貌特征

为了解铝青铜焊接热影响区(HAZ)的空蚀行为,对镍铝青铜焊接热影响区的空蚀形貌进行了扫描电镜(SEM)分析。结果表明:在空蚀初期,α相遭到选择性优先空蚀破坏;空蚀破坏呈现不均匀性,局部区域出现大的空蚀坑。热影响区空蚀破坏的机制是微坑的产生、长大、合并,进而形成裂纹,裂纹扩展最终导致失质。