Precipitation process in a cast alloy Al-3.5 wt.pct Zn-4 wt.pct Mg

✍ Scribed by Dr. Lecong Dzuong

• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: English
• Weight: 372 KB
• Volume: 15
• Category: Article
• ISSN: 0232-1300
• DOI: 10.1002/crat.19800150611

✦ Synopsis

Abstract

The structural changes during ageing of an alloy containing 3.5 wt.pct Zn and 4 wt.pct Mg were studied by means of transmission electron microscopy. It was shown that the precipitation process in this alloy differs from that in the alloys having high Zn/Mg ratios. The following phases were observed: hexagonal transition T′ phase, cubic stable T phase, hexagonal transition β′ phase, cubic stable β phase and hexagonal transition β′ phase. The precipitation process proposed the formation of two kinds of clusters in the beginning, i.e. Zn‐rich and Mg‐rich clusters. The former gradually transforms into GP zones and then into the T′ and T phases. The latter transforms into the β′ and β phases. The existence of the β′ phase seems to be a result of the segregation of the solute elements in the cast alloy.