GH4169真空感应过程夹杂物的演变机制

Evolution mechanism of inclusions in GH4169 produced by vacuum induction melting

高温合金中夹杂物是影响合金冶金质量和使用性能的主要因素,因此研究了GH4169镍基高温合金真空感应(VIM)熔炼制备过程中夹杂物的演变机制。采用真空感应炉对GH4169合金进行冶炼,通过ASPEX型自动扫描电镜分析检测夹杂物的物相组成、尺寸形貌及成分,并分析夹杂物的形成机理、来源及演变机制。结果表明,真空熔炼GH4169合金主要生成五种类型夹杂物:Al_(2)O_(3)、MgAl_(2)O_(4)和MgO单层夹杂物,MgAl_(2)O_(4)-Ti(C,N)-NbC和MgO-Ti(C,N)-NbC多层复合夹杂物。Al_(2)O_(3)在熔化期形成,MgAl_(2)O_(4)在精炼期形成,加入Nb、Al、Ti合金化后形成MgAl_(2)O_(4)-Ti(C,N)-NbC夹杂,加入Mg合金化后生成MgO和MgO-Ti(C,N)-NbC夹杂。随冶炼过程的进行,夹杂物的数量密度先增加后减少,在精炼期夹杂物数量密度达到峰值211.42个/mm^(2),精炼期结束后,夹杂物数量减少,出钢前夹杂物数量密度46.57个/mm^(2)。

Inclusion had been considered as main factor affecting metallurgical quality and mechanical property of Ni-based superalloys.In this work the evolution mechanism of inclusions during the preparation of GH4169 Ni-based superalloy by vacuum induction melting(VIM) was studied.A method of ASPEX automatic scanning electron microscope was utilized to characterize the inclusions in GH4169Ni-based superalloy prepared by vacuum induction melting(VIM).The phases,compositions,morphologies,formation mechanism and evolution mechanism of the inclusions were analyzed.The results indicate that the inclusions of single phase in GH4169 include mainly Al_(2)O_(3)、MgAl_(2)O_(4) and MgO.The inclusions of composite phases include mainly MgAl_(2)O_4-Ti(C,N)-NbC and MgO-Ti(C,N)-NbC.Al_(2)O_(3forms) during melting period,MgAl_(2)O_(4) forms during refining period,and MgAl_(2)O_4-Ti(C,N)-NbC forms after alloying with Nb,Al and Ti,and MgO and MgO-Ti(C,N)-NbC form after alloying with Mg.As smelting process going,the number density of inclusions firstly increases and then decreases,and the number density of inclusions reaches a peak value of 211.42/mm~2 during the refining period.After the refining period,the number of inclusions decreases,and the number density of inclusions before pouring is 46.57/mm~2.