Evaluation of pore Characterization in Powder Metallurgical Products Using Ultrasonic Scattering

本研究的目的是开发一种非破坏性的方法，用于评估孔隙结构的孔隙度和/或孔径的induatrial烧结压块通过使用超声波。为此，作者试图介绍一种超声衰减和速度测量的超声频谱学。本研究制备了六种不同孔径的铜烧结坯。这些由直径为400 μ m的气体雾化铜粉制成<micrn>。这些压坯结构简单，为孔-基体（Cu）双相结构，是建立工业烧结压坯超声孔结构表征方法的第一步最合适的样品。为了从超声衰减谱中评价孔隙结构，必须定量估计衰减谱。本研究探讨“频谱移动法”作为衰减频谱的定量估测方法。结果表明，用“频谱移动法”可以从超声衰减值估算平均孔径，而用超声声速测量值估算孔隙率。

The purpose of this investigation is to develop an non-destructive method for evaluating pore structures of porosity and/or pore size of induatrial sintered compacts by using ultrasonics. For this purpose, the suthors tried to introduce an ultrasonic spectroscopy of ultrasonic attenuation and velocity measurement. Six Cu-sintered compacts with different pore size were prepared for this study. These were made of gass-atomized copper powder of 400 <micrn> m in diameter. The structure of these compacts was simple, dual phase with pore and matrix (Cu), and was the most suitable sample for the first step to establish the method of ultrasonic pore structural charaterization for industrial sintered compacts. In order to evaluate the pore structures in paticular from the ultrasonic attenuation spectrum, the attenuation spactrum must be estimated quantitatively. In this study, "Spectrum Shifting Method" was investigated as the quantitative estimation method of attenuation spectrum. As the results, the mean pore diameter could be evaluated from the ultrasonic attenuation by using "Spectrum Shifting Method", and the poeosity could be estimated from ultrasonic velocity mesurement.