摘要
通过采用粉体致密化浸入式快速加热新工艺制备泡沫铝技术，研究了泡沫铝发泡早期气泡形成特征、早期气泡孔径结构特点及动态变化规律。结果表明：泡沫铝发泡历经以微膨胀、显著膨胀和塌陷收缩为特征的3个主要阶段；在发泡初期，微膨胀形成的机制主要是TiH2分解的H2，并受其受力状态所决定的，由此形成的裂纹式孔隙主要在固态，扩展方向呈横向特征。预制块的显著膨胀主要是由于TiH2的持续分解使裂纹式孔隙扩展长大的结果。由于新工艺加热升温迅速，发泡时间由一般的10min缩短为30—150s，使预制块固液态转换时间大大缩短，有效地提高了均匀发泡的动力学条件，同时还提高了TiH2的利用率。
Formation characteristics, aperture configuration and dynamic change of gas hole in the early stages of foamed aluminum were investigated based on preparation of foamed aluminum by a new powder metallurgy method with immersing preformer and heating up rapidly. The results show that foaming process is characterized by micro-propagation to macro-propagation to collapse. The formation mechanism of micro-propagation of crack-gas-hole depends on the stress from H_2 decomposed from TiH_2, characterized by transverse crack in propagation direction and distributed within solid phase. Macro-propagation is attributed to the crack propagation and growth resulting from continuous decomposition of TiH_2. The new method can reduce the heating time from 10 min to 30~150 s, which effectively increase the dynamic mechanism of homogeneous foaming and improve the utilization ratio of TiH_2.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2006年第3期136-138,共3页
Special Casting & Nonferrous Alloys
关键词
泡沫铝
粉末冶金
浸入法
TiH2
初期孔隙
Aluminum Foams, Powder Metallurgy, Immerging-making, TiH_2, Initial Crack
