قابليت رسوب سختي و مكانيزم رسوب گذاري در آلياژ منيزيم حاوي نيوديم و زيركنيم

Ageing Response and Precipitation Mechanism in a Magnesium Alloy Containing Neodymium and Zirconium

Magnesium alloys containing heavy rare earth elements are of considerable interest for aerospace and automotive applications, because of their high specific strength particularly in the age hardened condition. EK 10 in the T6 condition exhibits good room temperature and creep properties up to 200°C. in the present work ageing behavior of the alloy has been studied at temperatures 150, 200 and 250°C. Precipitates morphologies, crystal structure and crystallographic orientation relationship were also determined for various types of precipitates formed during ageing. The results showed that, plate-shaped ® precipitates with an ordered DO19 structure formed on ho lol,g planes, are responsible for the strength of the alloy. Further studies revealed that in the peak-hardening condition the alloy and some Oʹ precipitates. ®ʹ precipitates with a BCO structure were resultedʹ consisted of mainly during ageing process. Only incoherent ® precipitates with a FCC from in-situ transformation of structure were observed when ageing was carried out at 250°C and above.