Brake friction materials with different zinc powder contents(0,2,4,6,8 wt.%)were fabricated via powder metallurgy method.The results indicate that with the increasing zinc powder content,the density and thermal conduc...Brake friction materials with different zinc powder contents(0,2,4,6,8 wt.%)were fabricated via powder metallurgy method.The results indicate that with the increasing zinc powder content,the density and thermal conductivity of the materials gradually increase,while the hardness decreases monotonously.With increasing zinc powder content,the curve of the nominal friction coefficient shows fluctuating trend but the lowest friction coefficient also shows an increase.However,the wear rate and braking noise of the friction material monotonously decrease with increasing zinc content.This effect may be attributed to the transformation of the tribological mechanism from adhesive wear and abrasive wear to adhesive wear.The brake friction material with 4 wt.%zinc powder exhibits both the best tribological and noise performance.展开更多
Creep deformation can be classified as homogeneous flow and inhomogeneous flow in bulk metallic glass(BMG).In order to understand the conversion conditions of the two types of creep deformation,the effect of loading r...Creep deformation can be classified as homogeneous flow and inhomogeneous flow in bulk metallic glass(BMG).In order to understand the conversion conditions of the two types of creep deformation,the effect of loading rate on the creep behavior of a Ti_(40)Zr_(10)Cu_(47)Sn_(3)(at.%)BMG at ambient temperature was investigated using nanoindentation and molecular dynamic simulation.Results indicate that at low loading rates,many serrations appear in loading stage,leading to inhomogeneous serrated flow in the creep stage.When the loading rate is high enough,the creep deformation tends to be homogeneous.The related mechanism responsible for the rate-dependent creep behavior is attributed to the number of pre-existing major shear bands which is influenced significantly by the loading rate.展开更多
基金Project(2016YFB1100103)supported by the National Key Research and Development Program of ChinaProject(KC1703004)supported by the Science and Technology Planning Project of Changsha City,ChinaProject(2018ZZTS127)supported by the Fundamental Research Funds for the Central Universities of Central South University,China。
文摘Brake friction materials with different zinc powder contents(0,2,4,6,8 wt.%)were fabricated via powder metallurgy method.The results indicate that with the increasing zinc powder content,the density and thermal conductivity of the materials gradually increase,while the hardness decreases monotonously.With increasing zinc powder content,the curve of the nominal friction coefficient shows fluctuating trend but the lowest friction coefficient also shows an increase.However,the wear rate and braking noise of the friction material monotonously decrease with increasing zinc content.This effect may be attributed to the transformation of the tribological mechanism from adhesive wear and abrasive wear to adhesive wear.The brake friction material with 4 wt.%zinc powder exhibits both the best tribological and noise performance.
基金supported by the National Key Research and Development Program of China(No.2016YFB1100103)the National Natural Science Foundation of China(No.51771233)+2 种基金Key Research and Development Program of Hunan Province,China(No.2016JC2003)China Postdoctoral Science Foundation(No.2018M633164)Fundamental Research Funds for the Central Universities of Central South University,China(Nos.2018ZZTS127,CX20190190,2019ZZTS134)。
文摘Creep deformation can be classified as homogeneous flow and inhomogeneous flow in bulk metallic glass(BMG).In order to understand the conversion conditions of the two types of creep deformation,the effect of loading rate on the creep behavior of a Ti_(40)Zr_(10)Cu_(47)Sn_(3)(at.%)BMG at ambient temperature was investigated using nanoindentation and molecular dynamic simulation.Results indicate that at low loading rates,many serrations appear in loading stage,leading to inhomogeneous serrated flow in the creep stage.When the loading rate is high enough,the creep deformation tends to be homogeneous.The related mechanism responsible for the rate-dependent creep behavior is attributed to the number of pre-existing major shear bands which is influenced significantly by the loading rate.
