浇注工艺对K416B合金组织和持久性能的影响  

Effects of Pouring Process on Microstructure and Durability of K416B Alloy

作　　者：韦林 曹夕 王振江[2] 孙士杰 柴宏宇 盛乃成 侯桂臣[2] 康涌 王标 Wei Lin;Cao Xi;Wang Zhenjiang;Sun Shijie;Chai Hongyu;Sheng Naicheng;Hou Guichen;Kang Yong;Wang Biao(AECC Sichuan Gas Turbine Research Establishment;Institute of Metal Research,Chinese Academy of Sciences)

机构地区：[1]中国航发四川燃气涡轮研究院 [2]中国科学院金属研究所

出　　处：《特种铸造及有色合金》2022年第8期979-984,共6页Special Casting & Nonferrous Alloys

摘　　要：通过调整浇注温度及冷却方式制备了K416B镍基高温合金,对其组织形貌进行了观察分析,测试了在975℃、235 MPa条件下的持久性能,研究了浇注温度和冷却方式对K416B合金组织及持久性能的影响。结果表明,提高冷却速率可以减小铸态合金的枝晶间距,改变共晶形貌,同时减小γ′相尺寸。采用埋砂冷却获得的组织主要是大尺寸γ′共晶,而单壳冷却时以(γ+γ′)共晶为主。较高的浇注温度可增大铸态合金的晶粒尺寸,同时减小枝晶间残余共晶尺寸及含量,而对γ′尺寸的影响不大。在975℃、235 MPa条件下的持久断裂机制主要为裂纹沿晶界处、共晶与基体的界面处以及枝晶间缩松区域萌生及扩展。其中,在1 550℃浇注及单壳冷却的浇注工艺获得的晶粒尺寸较大,枝晶间共晶及缩松含量少且γ′相细小而均匀,是其具有较好持久性能的主要原因。The microstructure of K416 B nickel-based superalloy prepared by adjusting the pouring temperature and cooling method were observed and analyzed,and the durability at 975 ℃ and 235 MPa were tested to investigate the influence of pouring temperature and cooling method on microstructure and durability of K416 B alloy.The results indicate that with increasing in the cooling rate,the interdendritic distance of the as-cast alloy can be reduced,and the eutectic structure and the size of γ′ are refined.The large-size eutectic γ′ can be obtained in the as-cast structure of the alloy by sand cooling,which is mainly composed of(γ+γ′) eutectic by single shell cooling.A higher pouring temperature can increase the grain size of as-cast alloy and decrease the size and content of residual eutectic between dendrites,which has little effect on size of γ′.The persistent fracture mechanism of the alloy during stress rupture at 975 ℃ and 235 MPa is dominated by cracks initiation and propagation along the grain boundary,the interface between eutectic and matrix and the interdendritic loose area.Among them,grain size obtained by casting and single shell cooling at 1 550 ℃ is larger,and content of interdendritic eutectic and shrinkage is low with fine and uniform γ′ phase,which is the main reasons for desirable durability.

关 键 词：K416B合金 浇注工艺 显微组织 持久性能 

分 类 号：TG244[金属学及工艺—铸造]