The precipitation behavior of δ phase of 1 050 °C 1 h solution-treated GH4169 alloy aging treated at 800 ~980 °C and the dissolution rule of δ phase in alloy after 900 °C 20 h pre-precipitation treatment alloy solution-treating at 980 ~ 1 040 °C are studied. The results indicate that the peak temperature of δ phase precipitation occurred at approximately 900 °C. δ phase precipitates in grain boundary and twin boundary first

and δ phase transforms from granular to short rod and even needle. Intragranular δ phase transforms from γ" phase. Growing up mechanism of δ phase is influenced by temperature. δ phase dissolves during no less than 980 °C solution treated from δ phase boundaries first

and then transforms from needle to short rod and granular. Needle-δ phase in grain boundary dissolves faster

and transforms to short rod or granular. The δ phase shall be completely dissolves by solution-treated at ≥1 020 °C.