Three experimental single crystal superalloys with 0%Nb,0.5%Nb,1.0%Nb were cast in the directionally solidified furnace,while other alloying element contents were basically kept unchanged.The effect of Nb on the micro...Three experimental single crystal superalloys with 0%Nb,0.5%Nb,1.0%Nb were cast in the directionally solidified furnace,while other alloying element contents were basically kept unchanged.The effect of Nb on the microstructure,stability at1100°C and stress rupture properties at 1070°C and 160 MPa of the single crystal superalloy were investigated.The experiment results show that the primary dendrite arm spacing decreases and the volume fraction ofγ/γ′eutectic of the alloy increases with the increase of Nb content in the as-cast microstructures.The size ofγ′phase particles becomes small and uniform and the cubic shape does not obviously change with the increase of Nb content.The precipitating rate and volume fraction of TCP phases increase significantly with the increase of Nb content in the process of long term aging at 1100°C.The stress rupture lives increase and elongation decreases with increasing Nb content at 1070°C/160 MPa.At last,the relationship between the microstructures stability,stress rupture properties of the alloy and Nb content is discussed based on JMat Pro software and the lastest relevant database for single crystal superalloy.展开更多
通过对两种成分单晶镍基合金进行蠕变曲线测定,长期时效处理及组织形貌观察,研究了元素W含量对单晶合金组织与性能的影响。结果表明:在N i-A l-Cr-Ta-Co-x%W-5.5%Mo系单晶合金中,4wt%W合金在982℃,200MPa条件下,具有较长的蠕变寿命,随W...通过对两种成分单晶镍基合金进行蠕变曲线测定,长期时效处理及组织形貌观察,研究了元素W含量对单晶合金组织与性能的影响。结果表明:在N i-A l-Cr-Ta-Co-x%W-5.5%Mo系单晶合金中,4wt%W合金在982℃,200MPa条件下,具有较长的蠕变寿命,随W含量增加到6wt%,合金的蠕变寿命明显降低。高W合金在有/无应力时效期间,析出针状μ相,使合金基体出现难溶元素的贫化区,是导致合金蠕变寿命降低的主要原因。其中μ相在(001)晶面沿<110>方向呈相互平行、或垂直的针状形貌析出,沿{111}晶面呈片状方式生长,且与γ′相相邻。展开更多
文摘Three experimental single crystal superalloys with 0%Nb,0.5%Nb,1.0%Nb were cast in the directionally solidified furnace,while other alloying element contents were basically kept unchanged.The effect of Nb on the microstructure,stability at1100°C and stress rupture properties at 1070°C and 160 MPa of the single crystal superalloy were investigated.The experiment results show that the primary dendrite arm spacing decreases and the volume fraction ofγ/γ′eutectic of the alloy increases with the increase of Nb content in the as-cast microstructures.The size ofγ′phase particles becomes small and uniform and the cubic shape does not obviously change with the increase of Nb content.The precipitating rate and volume fraction of TCP phases increase significantly with the increase of Nb content in the process of long term aging at 1100°C.The stress rupture lives increase and elongation decreases with increasing Nb content at 1070°C/160 MPa.At last,the relationship between the microstructures stability,stress rupture properties of the alloy and Nb content is discussed based on JMat Pro software and the lastest relevant database for single crystal superalloy.
文摘通过对两种成分单晶镍基合金进行蠕变曲线测定,长期时效处理及组织形貌观察,研究了元素W含量对单晶合金组织与性能的影响。结果表明:在N i-A l-Cr-Ta-Co-x%W-5.5%Mo系单晶合金中,4wt%W合金在982℃,200MPa条件下,具有较长的蠕变寿命,随W含量增加到6wt%,合金的蠕变寿命明显降低。高W合金在有/无应力时效期间,析出针状μ相,使合金基体出现难溶元素的贫化区,是导致合金蠕变寿命降低的主要原因。其中μ相在(001)晶面沿<110>方向呈相互平行、或垂直的针状形貌析出,沿{111}晶面呈片状方式生长,且与γ′相相邻。
