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 通过对金属维氏硬度试验的不确定度的分析与计算,介绍一种维氏硬度试验不确定度的评定方法。     

维氏硬度试验的测量不确定度评定

利用FW214自动维氏硬度计,通过综合评定法对经校准的459HV10标块进行试验;并对测量结果的影响因素进行了分析,进而评定了维氏硬度试验的测量不确定度。结果表明：该试验室检测方法、检验水平能够满足GB/T 4340.2要求;综合评定法在提高检验效率的同时也能满足试验准确度需求。     

维氏硬度计稳定性测试

利用数理统计的方法对实验室维氏硬度计稳定性进行测试和评价,根据每次试验结果的测量不确定度建立\"测量不确定度随时间变化图\",对其使用情况作出有效评价.结果表明:硬度计运行稳定,满足检验要求.但压痕自动测量功能测量的硬度值常比实际数值稍大,建议对硬度计进行检查,调整因设备硬件造成的误差,保证结果更准确.     

A numerical fracture analysis of a stationary semi-circular interface crack during interfacial indentation test

The aim of this work is to investigate the fracture behavior of a stationary crack lying along the interface in a coated system during interfacial indentation test. One traditional 3D numerical model and one cohesive element numerical model have been made to study the Vickers indentation test process. A crack-block approach is applied to generate 3D meshes containing the crack front along the interface. The stress intensity factors and the energy release rates (G) on the crack front are computed. The fracture mode mixity is also presented. It is found that the near surface propagation of the crack can be prevented during loading due to compressive stresses. It may occur during unloading due to residual stresses resulting from plastic strain.     

A quantitative alternative to the Vickers hardness test based on a correlation between thermal diffusivity and hardness—applications to laser-hardened carburized steel

A quantitative non-destructive test technique for characterizing heat treated steel based on a theoretical model was developed and verified by experiments using the optical beam deflection technique at metallic samples, heated by a Gaussian beam. The analytic solution of the heat equation with appropriate approximations provides a theoretical expression of the surface temperature, which is an important guide to optimize the experimental process. Measurements have been focused on determining both, mechanical parameters and thermal local properties, in order to find correlations. The theoretically described thermal diffusivity was experimentally measured by using the new developed photo-thermal deflexion inversion procedure. A simple correlation between the micro-hardness according to Vickers and the thermal diffusivity was found for laser-hardened specimens depending on their microstructure and individual chemical composition.     

国外标准中洛氏硬度值测量不确定度的评定方法对比与分析

介绍了国际标准ISO／DIS6508．1—2004和美国ASTM E18标准中对金属洛氏硬度试验测量不确定度的评定方法，并对评定方法进行了比较和分析。     

基于仪器化Vickers压入比功与马氏硬度识别材料维氏硬度的方法

针对传统维氏硬度测试中因Vickers压痕形貌不清晰导致的维氏硬度无法识别问题,应用量纲定理和有限元数值分析方法对仪器化Vickers压入响应进行了系统分析,同时,结合维氏硬度有限元数值计算结果,揭示仪器化Vickers压入比功、马氏硬度与维氏硬度的近似函数关系。基于上述关系,提出由Vickers压入比功We/Wt和马氏硬度HM识别材料维氏硬度HV的新方法,对该方法进行测试精度分析,验证结果表明该方法较ISO14577中所提维氏硬度仪器化Vickers压入方法具有更高的测试精度。     

Production of high-density Ni-bonded tungsten carbide coatings using an axially fed DC-plasmatron

Using an axial feed DC-plasmatron, mixtures of fine Ni and WC powder (1–3 μm) were plasma sprayed onto stainless steel substrates. A series of high-density Ni–WC coatings were produces with uniform distribution of WC particles. The small powder sizes coupled with the axial feed system resulted in high vaporization rates of the Ni and significant decomposition of the WC powders. The high vaporization rate of Ni followed by condensation contributes to the high density of the coatings, while the high WC decomposition rate results in low WC content and low hardness values of the coatings. Based on published data and simple energy balance equations, evaporation of as much as 20% of the Ni powder was estimated, and XRD analysis indicates decomposition of as much as 80% of the WC particles.     

布氏硬度试验中测量不确定度的评定

介绍了测量硬度不确定度的原理，并以金属材料布氏硬度试验结果的不确定度的评定作为不确定度在理化检验中应用的一个实例。     

洛式硬度C标尺测量不确定度的评定及分析

通过对金属洛式硬度C标尺的不确定度评定与分析，介绍了不确定度的基本原理及其在硬度实验中的实践应用。