热处理对变形高铝Ni_3Al基合金组织及性能的影响

Effect of Heat Treatment on Structure and Properties of Deformed Ni_3Al-based Alloy with High Al Content

对热变形量56%的高铝Ni3Al基合金在热处理过程中的组织转变进行了研究。结果表明:热处理过程中随β-NiAl相的增大,γ+γ'相区不断向β+γ'相区扩展,借此消除锻后形成的γ'脆性晶界,提高锻后合金的塑性。在γ+γ'两相区,γ'相不断发生回溶;而在β+γ'两相区,随着M23C6向MCⅡ碳化物逆转变的进行,γ相以MCⅡ为形核质点发生再结晶长大。此外于扩大的γ相内有呈方形的粒状γ'相析出,与γ相保持完全共格,可提高合金高温强度。

The microstructure transformation was investigated for Ni3Al-based alloy containing high Al content under 56% hot deformation.The results show that： during the heat treatment,with the increase of the β-NiAl phase,the γ＋γ’ phase area has a continuous enlarging towards the β＋γ’ phase area,then the γ’ brittle grain boundary can get eliminated depend on that,which can improve the alloy plastic property.On the area of γ＋γ’ phase,the γ’ phase has a continuous solid-solution,while on the β＋γ’ phase area,with the inverse reaction for the M23C6 carbides changing into MCⅡ carbides happened,the MCⅡ carbides become to the nucleation sites for the γ phase.And some second γ’ phase about 1 μm can also be precipitated on the γ phase grain.Due to the second γ’ phase keeps coherence with the γ phase,the high temperature strength can be improved for the alloy.