محدوده دمایی برای تشکیل منطقه GP در آلیاژ آلومینیوم-منیزیم-روی

The Temperature Limit for GP Zone Formation

in an Al-Zn-Mg Alloy

محدوده دمایی برای تشکیل منطقه GP در آلیاژ آلومینیوم-منیزیم-روی  

ABSTRACT

The temperature limit for GP zone formation, Tlimit was determined for an Al-5 pct Zn-2 pct Mg alloy by examining the formation process of the intermediate phase. Studies of changes in hardness and electrical resistivity, together with electron metallography permitted a conclusion that the Tlimit for this alloy is 125 °C. The nucleation mechanism of the intermediate phase is also discussed. Two types of precipitation mode were found the partly coherent phase;i.e. heterogeneous nucleation on GP zones and homogeneous nucleation respectively. It is concluded that the dominant nucleation mode is determined by the quenching conditions.