Nickel-based superalloy(GH4169)is an ideal material for preparing turbine blades.Profile grinding of the fir-treeshaped turbine blade root can easily cause thermal damage to the workpiece specimen.This study aims to e...Nickel-based superalloy(GH4169)is an ideal material for preparing turbine blades.Profile grinding of the fir-treeshaped turbine blade root can easily cause thermal damage to the workpiece specimen.This study aims to enhance the suppression of alloy thermal damage by regulating the thickness of the oxide film on the cubic boron nitride(CBN)grinding wheel during the electrolytic in-process dressing(ELID)-assisted grinding process.A theoretical model for calculating the thickness of oxide film in ELID-assisted grinding was developed.Finite element simulation was conducted using the electrolytic film-forming process of the grinding wheel.The effects of electrical/nonelectrical parameters on the oxide film characteristics and grinding responses were addressed.The optimal matching scheme of process parameters was established.The results showed that the film layer of the grinding wheel at the blade root cam is more seriously damaged,and the workpiece surface is rougher.Further optimization of the electrode is demanded to achieve different dressing effects at various positions of the grinding wheel based on the workpiece profile.By reducing the interelectrode gap(h_(e)),increasing the power supply voltage(E_(o)),and controlling the electrolysis time(△t)at 10-15 min,the preferred film-forming efficiency and grinding quality can be achieved.By increasing the grinding wheel speed(V_(s))or decreasing the workpiece feed rate(V_(f))and grinding depth(a_(p)),the grinding thermal damage can be suppressed.A larger value of V_(f)or apcan be selected to acquire a compromise between grinding quality and film-forming efficiency after increasing the value of Vs.The optimal combination of electrical and nonelectrical parameters during this test is E_(o)=120 V,△t=15 min,h_(e)=0.1 mm,V_f=50 mm min^(-1),V_s=30 m s^(-1),and a_(p)=0.4 mm.展开更多
Development of effective treatments for neurodegenerative disorders is a clinical conundrum that has puzzled many researchers.Currently available drugs target symptomatic relief rather than suppressing,ceasing or repa...Development of effective treatments for neurodegenerative disorders is a clinical conundrum that has puzzled many researchers.Currently available drugs target symptomatic relief rather than suppressing,ceasing or repairing the devastating neural damages.For Alzheimer’s disease,two classes of procognitive compounds are approved as a treatment.展开更多
基金supported by the Shanghai“Explorer Program”Project(Grant No.24TS1414500)the 10th Sino-Hungarian Intergovernmental Scientific and Technological Cooperation Project(Grant No.2024-10-2)。
文摘Nickel-based superalloy(GH4169)is an ideal material for preparing turbine blades.Profile grinding of the fir-treeshaped turbine blade root can easily cause thermal damage to the workpiece specimen.This study aims to enhance the suppression of alloy thermal damage by regulating the thickness of the oxide film on the cubic boron nitride(CBN)grinding wheel during the electrolytic in-process dressing(ELID)-assisted grinding process.A theoretical model for calculating the thickness of oxide film in ELID-assisted grinding was developed.Finite element simulation was conducted using the electrolytic film-forming process of the grinding wheel.The effects of electrical/nonelectrical parameters on the oxide film characteristics and grinding responses were addressed.The optimal matching scheme of process parameters was established.The results showed that the film layer of the grinding wheel at the blade root cam is more seriously damaged,and the workpiece surface is rougher.Further optimization of the electrode is demanded to achieve different dressing effects at various positions of the grinding wheel based on the workpiece profile.By reducing the interelectrode gap(h_(e)),increasing the power supply voltage(E_(o)),and controlling the electrolysis time(△t)at 10-15 min,the preferred film-forming efficiency and grinding quality can be achieved.By increasing the grinding wheel speed(V_(s))or decreasing the workpiece feed rate(V_(f))and grinding depth(a_(p)),the grinding thermal damage can be suppressed.A larger value of V_(f)or apcan be selected to acquire a compromise between grinding quality and film-forming efficiency after increasing the value of Vs.The optimal combination of electrical and nonelectrical parameters during this test is E_(o)=120 V,△t=15 min,h_(e)=0.1 mm,V_f=50 mm min^(-1),V_s=30 m s^(-1),and a_(p)=0.4 mm.
文摘Development of effective treatments for neurodegenerative disorders is a clinical conundrum that has puzzled many researchers.Currently available drugs target symptomatic relief rather than suppressing,ceasing or repairing the devastating neural damages.For Alzheimer’s disease,two classes of procognitive compounds are approved as a treatment.
