高温合金Inconel718、Inconel706和Inconel706M电渣重熔组织均匀性

对比研究了高温合金Inconel 718、Inconel 706和Inconel 706M电渣重熔铸锭的枝晶组织和析出相差异。结果表明,在3种高温合金中,718铸锭中心区域的枝晶间距与边缘区域的差值最小,并且主要偏析元素Nb和Ti在铸锭中心的偏析率与边缘的差异也最小,718铸锭的宏观组织均匀性最好;706M铸锭中心与边缘的枝晶间距差值最大,且铸锭中心的Nb元素偏析率与边缘的差异达到0.91%,铸锭宏观组织均匀性最差。718铸锭枝晶间易富集正偏析元素Nb和Mo,最高含量分别达到6.82%和3.01%;706、706M铸锭枝晶间最高Nb含量均低于4%,Ti元素含量最高均达到2%以上,同时706及706M铸锭组织中Nb的偏析率依然很大。706铸锭组织中Laves相最多,中心位置Laves相含量达到3.9%,边缘含量降低超过2%,分布不均匀;706M铸锭组织中Laves相最少,中心及边缘含量均低于2%,含量分布比较均匀。与718和706相比,706M铸锭中心区域的碳氮化物平均长度与边缘的差异最大,且组织中存在更少的针状相。

Homogeneity of Electroslag Remelting Microstructure of Superalloy Inconel 718,Inconel 706 and Inconel 706M

The dendrite structure and precipitation phase differences of electroslag remelting ingot of Inconel 718, Inconel706 and Inconel 706M were studied. The results show that among the three kinds of superalloys, the difference between the dendrite spacing in the center of 718 ingots and the edge is the smallest, and the difference between the segregation rate of the main segregation elements Nb and Ti in the center of 718 ingots and the edge region is the smallest, and the macroscopic microstructure uniformity of 718 ingots is the best. The dendrite spacing difference between the center and the edge of 706M ingots is the largest, and the difference between the Nb element segregation rate in the center of the ingots and the edge is 0.91%. The microstructure uniformity of the ingots is the worst. 718 ingot dendrites are prone to enrich positive segregation elements Nb and Mo, with the highest contents reaching 6.82% and 3.01%, respectively. The highest Nb content between dendrites of 706 and 706M ingots is less than 4%, and the highest Ti element content is more than 2%. Meanwhile, the Nb segregation rate in the microstructure of 706 and 706M ingots is still very high. The phase of Laves in 706 ingot structure is the most, and the phase content of Laves in the center reach 3.9%, and the edge content decrease by more than 2%, with uneven distribution. 706M Laves phase is the least in the cast ingot structure, and the content in the center and edge is less than 2%. The content distribution is relatively uniform. Compared with 718 and 706,the average length of carbonitrides in the central region of 706M ingots varied the most from the edge, and there are fewer acicular phases in the microstructure.