The WC particle-reinforced copper matrix composites with WC content in the range of 5 vol%-30 vol%were prepared and investigated by micro-scratch tests under the loads of 1-4 N.The influences of normal load and WC con...The WC particle-reinforced copper matrix composites with WC content in the range of 5 vol%-30 vol%were prepared and investigated by micro-scratch tests under the loads of 1-4 N.The influences of normal load and WC content on friction coefficient and wear volume of the composites were studied.The hardness and scratch resistance of the composites are greatly improved by the addition of WC.The penetrate depth and residual depth increase near-linearly with normal load increasing and decrease with WC content increasing,and the friction coefficient of the composites also shows the same variation trend.The valid material removal mechanism is found to transform from micro-plowing to micro-cutting as the normal load increases.展开更多
In this study two types of TIN films were prepared, one using the filtered cathodic arc plasma （FCAP） technique with an in-plane ＂S＂ triter, and the other using the multi-arc ion-plating （MAIP）, and both deposit...In this study two types of TIN films were prepared, one using the filtered cathodic arc plasma （FCAP） technique with an in-plane ＂S＂ triter, and the other using the multi-arc ion-plating （MAIP）, and both deposited under the same parameters. Comparisons of the texture, hardness, roughness, tribological and electrochemical corrosion behaviors of the two types of TiN films were given. The TiN films obtained by the FCAP technology were found to be highly uniform, smooth and macroparticle-free. The TiN films deposited by FCAP had a （111） preferred orientation, while there was no texture in the films deposited by MAIP. Under low load the two kinds of TiN coatings had very different wear mechanisms; the films of FCAP had a lower wear rate and friction coefficient compared with the TiN films deposited by the MAIP technique. The dense and hole-free structure of TiN films of FCAP could effectively avoid the avalanche of TiN films from the substrate during corrosion tests.展开更多
The interface adhesion strength(or interface toughness)of a thin film/substrate system is often assessed by the micro-scratch test.For a brittle film material,the interface adhesion strength is easily obtained through...The interface adhesion strength(or interface toughness)of a thin film/substrate system is often assessed by the micro-scratch test.For a brittle film material,the interface adhesion strength is easily obtained through measuring the scratch driving forces.However,to measure the interface adhesion strength(or in- terface toughness)for a metal thin film material(the ductile material)by the micro- scratch test is very difficult,because intense plastic deformation is involved and the problem is a three-dimensional elastic-plastic one.In the present research,using a double-cohesive zone model,the failure characteristics of the thin film/substrate system can be described and further simulated.For a steady-state scratching pro- cess,a three-dimensional elastic-plastic finite element method based on the double cohesive zone model is developed and adopted,and the steady-state fracture work of the total system is calculated.The parameter relations between the horizontal driving forces(or energy release rate of the scratching process)and the separation strength of thin film/substrate interface,and the material shear strength,as well as the material parameters are developed.Furthermore,a scratch experiment for the Al/Si film/substrate system is carried out and the failure mechanisms are explored. Finally,the prediction results are applied to a scratch experiment for the Pt/NiO material system given in the literature.展开更多
Dry wear behavior of the rheo-casting Al-16Si-4Cu-0.5Mg alloy was investigated by micro-scratch and dry sliding weartests. Analyses of the microstructure, scratch grooves, wear tracks, worn surfaces and wear debris of...Dry wear behavior of the rheo-casting Al-16Si-4Cu-0.5Mg alloy was investigated by micro-scratch and dry sliding weartests. Analyses of the microstructure, scratch grooves, wear tracks, worn surfaces and wear debris of the alloy were carried out byoptical microscope and scanning electron microscope. The microstructural analysis showed that via rheo-processing, the primary Siwas refined and rounded, eutectics dispersed more homogenously, and even the skeleton AlFeMnSi phase was fragmented into facetshape. Micro-scratch test showed that the microstructural refinement resulted in better wear resistance. Dry sliding wear test revealedthat the rheo-processed sample exhibit obviously superior wear resistance because of the microstructure improvement. The dominantmechanism in mild wear condition is abrasion, but it turned to adhesion and oxidation in high applied load and fast sliding velocityconditions.展开更多
基金Project(2021JJ30577) supported by Hunan Provincial Natural Science Foundation of ChinaProject(X202110555425) supported by College Students Innovation and Entrepreneurship Training Program of University of South China。
基金financially supported by the National Natural Science Foundation of China (Nos. 21175157 and 21375151)
文摘The WC particle-reinforced copper matrix composites with WC content in the range of 5 vol%-30 vol%were prepared and investigated by micro-scratch tests under the loads of 1-4 N.The influences of normal load and WC content on friction coefficient and wear volume of the composites were studied.The hardness and scratch resistance of the composites are greatly improved by the addition of WC.The penetrate depth and residual depth increase near-linearly with normal load increasing and decrease with WC content increasing,and the friction coefficient of the composites also shows the same variation trend.The valid material removal mechanism is found to transform from micro-plowing to micro-cutting as the normal load increases.
基金the National Natural Science Foundation of China (No. 20571042)the Natural Science Foundation of the Education Department of Henan Province, China (No. 2007430001)the Natural Science Foundation of Henna University (No. 06YBZR008).
文摘In this study two types of TIN films were prepared, one using the filtered cathodic arc plasma （FCAP） technique with an in-plane ＂S＂ triter, and the other using the multi-arc ion-plating （MAIP）, and both deposited under the same parameters. Comparisons of the texture, hardness, roughness, tribological and electrochemical corrosion behaviors of the two types of TiN films were given. The TiN films obtained by the FCAP technology were found to be highly uniform, smooth and macroparticle-free. The TiN films deposited by FCAP had a （111） preferred orientation, while there was no texture in the films deposited by MAIP. Under low load the two kinds of TiN coatings had very different wear mechanisms; the films of FCAP had a lower wear rate and friction coefficient compared with the TiN films deposited by the MAIP technique. The dense and hole-free structure of TiN films of FCAP could effectively avoid the avalanche of TiN films from the substrate during corrosion tests.
基金The project supported by the National Natural Science Foundation of China (19891180 and 19925211)Bai Ren Plan of CAS
文摘The interface adhesion strength(or interface toughness)of a thin film/substrate system is often assessed by the micro-scratch test.For a brittle film material,the interface adhesion strength is easily obtained through measuring the scratch driving forces.However,to measure the interface adhesion strength(or in- terface toughness)for a metal thin film material(the ductile material)by the micro- scratch test is very difficult,because intense plastic deformation is involved and the problem is a three-dimensional elastic-plastic one.In the present research,using a double-cohesive zone model,the failure characteristics of the thin film/substrate system can be described and further simulated.For a steady-state scratching pro- cess,a three-dimensional elastic-plastic finite element method based on the double cohesive zone model is developed and adopted,and the steady-state fracture work of the total system is calculated.The parameter relations between the horizontal driving forces(or energy release rate of the scratching process)and the separation strength of thin film/substrate interface,and the material shear strength,as well as the material parameters are developed.Furthermore,a scratch experiment for the Al/Si film/substrate system is carried out and the failure mechanisms are explored. Finally,the prediction results are applied to a scratch experiment for the Pt/NiO material system given in the literature.
基金Project(51404153)supported by the National Natural Science Foundation of ChinaProject supported by the Joint Ph D Program of the China Scholarship Council(CSC)
文摘Dry wear behavior of the rheo-casting Al-16Si-4Cu-0.5Mg alloy was investigated by micro-scratch and dry sliding weartests. Analyses of the microstructure, scratch grooves, wear tracks, worn surfaces and wear debris of the alloy were carried out byoptical microscope and scanning electron microscope. The microstructural analysis showed that via rheo-processing, the primary Siwas refined and rounded, eutectics dispersed more homogenously, and even the skeleton AlFeMnSi phase was fragmented into facetshape. Micro-scratch test showed that the microstructural refinement resulted in better wear resistance. Dry sliding wear test revealedthat the rheo-processed sample exhibit obviously superior wear resistance because of the microstructure improvement. The dominantmechanism in mild wear condition is abrasion, but it turned to adhesion and oxidation in high applied load and fast sliding velocityconditions.
