Inter-particle bonding is an important factor affecting the property of cold sprayed metallic deposit.Because the interface bonding between particles in deposit is directly determined by plastic strain of particles du...Inter-particle bonding is an important factor affecting the property of cold sprayed metallic deposit.Because the interface bonding between particles in deposit is directly determined by plastic strain of particles during spraying,Cu deposits were made at series of impact velocities of 578 m s^-1 to 745 m s^-1 and 807 m s^-1 to correlate particle impact condition with microstructure and properties of the deposits.Results show that as the average particle impact velocity increases from 578 m s^-1 to 745 m s^-1 and 807 m s^-1,the deposition efficiency of feedstock powder increases from 58%to 84%and even to 95%.Although all three deposits reveal dense microstructure due to the high ductility of Cu,the deformation degree of the deposited particles remarkably increases with increasing impact velocity.The enhanced plastic deformation of the deposited particles leads to more dispersed oxide scale and thereby stronger interparticle bonding with the strength of the deposit along the deposition direction increasing from 25.8 MPa to 148.5 MPa.The electrical and thermal conductivities at through-thickness direction of the deposit at particle impact velocity of 807 m s^-1 are 78%IACS,295 W m^-1 K^-1,respectively.展开更多
In this study, the effects of the impact velocity on the particle deposition characteristics in cold gas dynamic spraying （CGDS） of 304 stainless steel （SS） on an interstitial free （IF） steel substrate are numer...In this study, the effects of the impact velocity on the particle deposition characteristics in cold gas dynamic spraying （CGDS） of 304 stainless steel （SS） on an interstitial free （IF） steel substrate are numerical simulated by means of a finite element analysis （FEA）. The results have illustrated that when the particle impact velocity exceeds a critical value at which adiabatic shear instability of the particle starts to occur. Meanwhile, the fatten ratio and impact crater depth （or the effective contacting area ） increase rapidly. The particle-substrate bonding and deposition mechanism can be attributed to such an adiabatic shear deformation induced by both the compressive force and the slide friction force of particle. The critical velocity can be predicted by numerical simulation, which is useful to optimize the CGDS processing parameters for various materials.展开更多
基金financially supported by the National Nature Science Foundation of China(Grant Nos.51875443 and 51401158)the Shaanxi Co-Innovation Projects(Grant No.2015KTTSGY03-03)the Fund from The Key Lab of Guangdong for Modern Surface Engineering Technology and the Shaanxi Natural Science Foundation(Grant No.2015JQ5200).
文摘Inter-particle bonding is an important factor affecting the property of cold sprayed metallic deposit.Because the interface bonding between particles in deposit is directly determined by plastic strain of particles during spraying,Cu deposits were made at series of impact velocities of 578 m s^-1 to 745 m s^-1 and 807 m s^-1 to correlate particle impact condition with microstructure and properties of the deposits.Results show that as the average particle impact velocity increases from 578 m s^-1 to 745 m s^-1 and 807 m s^-1,the deposition efficiency of feedstock powder increases from 58%to 84%and even to 95%.Although all three deposits reveal dense microstructure due to the high ductility of Cu,the deformation degree of the deposited particles remarkably increases with increasing impact velocity.The enhanced plastic deformation of the deposited particles leads to more dispersed oxide scale and thereby stronger interparticle bonding with the strength of the deposit along the deposition direction increasing from 25.8 MPa to 148.5 MPa.The electrical and thermal conductivities at through-thickness direction of the deposit at particle impact velocity of 807 m s^-1 are 78%IACS,295 W m^-1 K^-1,respectively.
文摘In this study, the effects of the impact velocity on the particle deposition characteristics in cold gas dynamic spraying （CGDS） of 304 stainless steel （SS） on an interstitial free （IF） steel substrate are numerical simulated by means of a finite element analysis （FEA）. The results have illustrated that when the particle impact velocity exceeds a critical value at which adiabatic shear instability of the particle starts to occur. Meanwhile, the fatten ratio and impact crater depth （or the effective contacting area ） increase rapidly. The particle-substrate bonding and deposition mechanism can be attributed to such an adiabatic shear deformation induced by both the compressive force and the slide friction force of particle. The critical velocity can be predicted by numerical simulation, which is useful to optimize the CGDS processing parameters for various materials.
