W및 Cu-粉末 成形體의 收縮比에 관하여

Abstract

기계적 성질을 달리하는 Cu및 W 분말성형체에서 소결시 收縮異方性에 미치는 粉末粒度, 成形壓, 燒結 시간의 영향을 조사하고 燒結進行에 따르는 收縮比의 거동을 알아 보았다.

W분말 성형체에서는 收縮比는 微細한 粉末粒度에서 보다 安定한 값을 나타내었으며 粗大한 粒度에서는 燒結初期에 成形壓의 영향이 현저하게 나타났고 그 이후의 燒結進行에 따른 成形壓의 영향은 보이지 않았다.

Cu-분말 성형체에서는 粗大한 분말 성형체에서 소결이 진형됨에 따른 R/A에 미치는 성형壓의 영향은 현저하며 적은 성형壓에서 보다 큰 收縮比値를 보여 주었다.

소결시 소결단계에 따른 조밀화, 재배열 과정에서 소결체 內의 氣孔의 형상학적 거동이 收縮比에 미치는 영향을 논의하였다.

The anisotropic shrinkage during sintering in compacts made of tungsten and copper powder with irregular shape has been investigated as function of powder particle size, compacting pressure and sintering time. The behavior of radial/axial(R/A) shrinkage ratio throughout the sintering process has been studied.

Tungsten powder compacts showed more stable value of R/A ratio for smaller particle size. The influence of compacting pressure on R/A ratio for coarse powder compacts was pronounced in the early stage of sintering but became negligible in the later stage.

In the case of coarser powder compacts of copper, the R/A ratio was found to be strongly affected by the sintering process and the compacting pressure; e.g., the lower the compacting pressure was, the higher the R/A ratio was observed.

The possible morphological changes of residual pores in the early and later stages of sintering, such as anisotropy and densification due to rearrangement of particles, was discussed together with other factors to explain the phenomena.

The anisotropic shrinkage during sintering in compacts made of tungsten and copper powder with irregular shape has been investigated as function of powder particle size, compacting pressure and sintering time. The behavior of radial/axial(R/A) shrinkage ratio throughout the sintering process has been studied.

Tungsten powder compacts showed more stable value of R/A ratio for smaller particle size. The influence of compacting pressure on R/A ratio for coarse powder compacts was pronounced in the early stage of sintering but became negligible in the later stage.

In the case of coarser powder compacts of copper, the R/A ratio was found to be strongly affected by the sintering process and the compacting pressure; e.g., the lower the compacting pressure was, the higher the R/A ratio was observed.

The possible morphological changes of residual pores in the early and later stages of sintering, such as anisotropy and densification due to rearrangement of particles, was discussed together with other factors to explain the phenomena.