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 est...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.展开更多
The repair welding of UNS C95700manganese?aluminum bronze plates was done using different filler metals.Themicrostructure and mechanical properties of welds were studied.The main microstructural constituents wereα,β...The repair welding of UNS C95700manganese?aluminum bronze plates was done using different filler metals.Themicrostructure and mechanical properties of welds were studied.The main microstructural constituents wereα,βandκphases withdifferent morphologies.The addition of manganese decreased the percentage ofαphase in the microstructure of weldments from80%(Mn-free weld)to57%(12.5%Mn weld,mass fraction).The morphology ofκphase was lamellar in high nickel specimens andit was changed to a globular morphology for high manganese welds.Although the application of high manganese filler metal yieldedthe higher tensile and bending strengths of weldment compared with the weld using high nickel filler material,the optimummechanical properties of repair welds were obtained using a non-alloy filler material(ERCuAl-A2)for the underlay and highmanganese filler metal(ERCuMnNiAl)for filling passes.This weld presented an increase of39%in tensile strength compared withthe base metal,and no cracking was observed after bending test.展开更多
Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 h...Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.展开更多
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 annea...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.展开更多
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 we...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.展开更多
The directional structure of Ni60/high-aluminum bronze composite coating was formed using induction remelting and forced cooling.The microstructural evolution and the characteristics of interface growth were studied.T...The directional structure of Ni60/high-aluminum bronze composite coating was formed using induction remelting and forced cooling.The microstructural evolution and the characteristics of interface growth were studied.The results showed that the remelted coating formed metallurgical bonding with the substrate.The micros tructures changed from plane crystal to dendrite,cellular dendrite,fine cellular dendrite,and then to dendrite again with the increase in the cooling rate.The crystal grew along the heat flow direction and had(111) and(200)preferred orientations when the cooling rate was 1.886 ml-min^(-1).mm^(-2).The plane crystal,dendrite and cellular dendrite were mainly composed of compounds and solid solutions with Ni,Fe and Cu,and they were surrounded by strengthening phases composed of Cr,C and B.The grain boundary of directional structure coatings showed the characteristic of regular eutectic growth,but grain boundary of remelted coating presented characteristic of divorced eutectic growth.The wear resistance of directional structure coatings is better than that of remelted coating.展开更多
Wear behavior and mechanism of plasma nitrided steel oscillating against a heat-treated and an untreated aluminum bronze alloy were investigated using an Optimol SRV tribometer.The influence of heat treatment on the m...Wear behavior and mechanism of plasma nitrided steel oscillating against a heat-treated and an untreated aluminum bronze alloy were investigated using an Optimol SRV tribometer.The influence of heat treatment on the mechanical properties of the alloy was evaluated.Furthermore,the wear debris was also examined to understand the wear mechanisms.The results show that a 220-230μm nitrided layer,which was harder than the substrate,was obtained on the steel surface.The tensile strength and hardness of the alloy are found to be significantly improved by the heat treatment associated with low impact toughness.The heat treatment of the alloy did not obviously decrease the friction coefficient of the nitrided steel-bronze couple.However,the wear loss of the nitrided steel increased when it mated with the treated bronze by a severe three-body abrasion.The nitrided steel was mainly damaged by fatigue spalling.Under plane contact conditions,the wear debris was mainly generated from the bronze part and can escape from the interface before being oxidized,leading to the phase structure of all the debris being copper rather than copper oxides.展开更多
A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma spray...A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma sprayed on the 45# medium carbon steel substrate. The effect of rare earth Ce on the microstructures and Vickers hardness of the cast alloy and coatings were characterized by scanning electron microscopy, X-ray diffraction, electronic probe microanalysis, transmission electron microscopy and microhardness measurements. The results indicate that the hardness of both as-cast alloy and coating are enhanced by the addition of 0.6% Ce due to the refinement of κ phases which are well distributed in the matrix. The rapid solidification in the plasma spray processing retains Fe-supersaturated in the Al-bronze alloy coatings, which avoids the formation of eutectoid （α＋γ2） phase and stacking faults are found in the coatings with Ce added, accordingly improves the mechanical properties.展开更多
基金Project(2014CB046704)supported by the National Basic Research Program of ChinaProject(2014BAB13B01)supported by the National Science and Technology Pillar Program of China
文摘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.
文摘The repair welding of UNS C95700manganese?aluminum bronze plates was done using different filler metals.Themicrostructure and mechanical properties of welds were studied.The main microstructural constituents wereα,βandκphases withdifferent morphologies.The addition of manganese decreased the percentage ofαphase in the microstructure of weldments from80%(Mn-free weld)to57%(12.5%Mn weld,mass fraction).The morphology ofκphase was lamellar in high nickel specimens andit was changed to a globular morphology for high manganese welds.Although the application of high manganese filler metal yieldedthe higher tensile and bending strengths of weldment compared with the weld using high nickel filler material,the optimummechanical properties of repair welds were obtained using a non-alloy filler material(ERCuAl-A2)for the underlay and highmanganese filler metal(ERCuMnNiAl)for filling passes.This weld presented an increase of39%in tensile strength compared withthe base metal,and no cracking was observed after bending test.
基金This work was financially supported by National Nature Science Foundation of China (No.50075026)and Education Ministry of China (No.[2000]65)and research funding from Guangdong Provincial High Education Department (Thousand, Hundred Ten Project).]
文摘Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.
基金financially supported by the Fundamental Research Funds for the Central Universities of China (Nos. B210203049, B210204005)the Natural Science Foundation of Jiangsu Province, China (No. BK20191161)+1 种基金the Changzhou Sci & Tech Program, China (No. CJ20210154)the National Natural Science Foundation of China (Nos. 51601058, 51879089)
文摘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.
文摘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.
基金financially supported by the National Natural Science Foundation of China(No.51365024)Zhejiang Provincial Natural Science Foundation of China(No.LGG19E010003)。
文摘The directional structure of Ni60/high-aluminum bronze composite coating was formed using induction remelting and forced cooling.The microstructural evolution and the characteristics of interface growth were studied.The results showed that the remelted coating formed metallurgical bonding with the substrate.The micros tructures changed from plane crystal to dendrite,cellular dendrite,fine cellular dendrite,and then to dendrite again with the increase in the cooling rate.The crystal grew along the heat flow direction and had(111) and(200)preferred orientations when the cooling rate was 1.886 ml-min^(-1).mm^(-2).The plane crystal,dendrite and cellular dendrite were mainly composed of compounds and solid solutions with Ni,Fe and Cu,and they were surrounded by strengthening phases composed of Cr,C and B.The grain boundary of directional structure coatings showed the characteristic of regular eutectic growth,but grain boundary of remelted coating presented characteristic of divorced eutectic growth.The wear resistance of directional structure coatings is better than that of remelted coating.
文摘Wear behavior and mechanism of plasma nitrided steel oscillating against a heat-treated and an untreated aluminum bronze alloy were investigated using an Optimol SRV tribometer.The influence of heat treatment on the mechanical properties of the alloy was evaluated.Furthermore,the wear debris was also examined to understand the wear mechanisms.The results show that a 220-230μm nitrided layer,which was harder than the substrate,was obtained on the steel surface.The tensile strength and hardness of the alloy are found to be significantly improved by the heat treatment associated with low impact toughness.The heat treatment of the alloy did not obviously decrease the friction coefficient of the nitrided steel-bronze couple.However,the wear loss of the nitrided steel increased when it mated with the treated bronze by a severe three-body abrasion.The nitrided steel was mainly damaged by fatigue spalling.Under plane contact conditions,the wear debris was mainly generated from the bronze part and can escape from the interface before being oxidized,leading to the phase structure of all the debris being copper rather than copper oxides.
基金Projects (50804019, 51165021) supported by the National Natural Science Foundation of ChinaProject (0901ZTB009) supported by the Super Tutor Foundation from the Education Department of Gansu Province, China
文摘A novel aluminum bronze over the Cu-Al binary alloy eutectoid Cu-14Al-4.5Fe was prepared by a jointly-charging one-melting technique and conventional sand casting. The bronze coatings were atmospherically plasma sprayed on the 45# medium carbon steel substrate. The effect of rare earth Ce on the microstructures and Vickers hardness of the cast alloy and coatings were characterized by scanning electron microscopy, X-ray diffraction, electronic probe microanalysis, transmission electron microscopy and microhardness measurements. The results indicate that the hardness of both as-cast alloy and coating are enhanced by the addition of 0.6% Ce due to the refinement of κ phases which are well distributed in the matrix. The rapid solidification in the plasma spray processing retains Fe-supersaturated in the Al-bronze alloy coatings, which avoids the formation of eutectoid （α＋γ2） phase and stacking faults are found in the coatings with Ce added, accordingly improves the mechanical properties.
