Tensile, creep behavior and microstructure evolution of an as-cast Ni-based K417G polycrystalline superalloy
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2018年第10期
论文作者：Beining Du Ziyang Hu Liyuan Sheng Chuanyong Cui Jinxia Yang Yufeng Zheng Xiaofeng Sun
文章页码：1805 - 1816
摘 要：The Ni-based K417 G superalloy is extensively applied as aeroengine components for its low cost and good mid-temperature（600–900?C） properties. Since used in as-cast state, the comprehensive understanding on its mechanical properties and microstructure evolution is necessary. In the present research,the tensile, creep behavior and microstructure evolution of the as-cast K417 G superalloy under different conditions were investigated. The results exhibit that tensile cracks tend to initiate at MC carbide and γ/γ’ eutectic structure and then propagate along grain boundary. As the temperature for tensile tests increases from 21?C to 700?C, the yield strength and ultimate tensile strength of K417 G superalloy decreases slightly, while the elongation to failure decreases greatly because of the intermediate temperature embrittlement. When the temperature rises to 900?C, the yield strength and ultimate tensile strength would decrease significantly. The creep deformation mechanism varies under different testing conditions. At 760?C/645 MPa, the creep cracks initiate at MC carbides and γ/γ’ eutectic structures,and propagate transgranularly. While at 900?C/315 MPa and 950?C/235 MPa, the creep cracks initiate at grain boundary and propagate intergranularly. As the creep condition changes from 760?C/645 MPa to 900?C/315 MPa and 950?C/235 MPa, the ? phase starts to raft, which reduces the creep deformation resistance and increases the steady-state deformation rate.
Beining Du1，Ziyang Hu1,2，Liyuan Sheng1，Chuanyong Cui3，Jinxia Yang3，Yufeng Zheng1，Xiaofeng Sun3
1. Shenzhen Institute, Peking University3. Institute of Metal Research, Chinese Academy of Sciences
摘 要：The Ni-based K417 G superalloy is extensively applied as aeroengine components for its low cost and good mid-temperature（600–900?C） properties. Since used in as-cast state, the comprehensive understanding on its mechanical properties and microstructure evolution is necessary. In the present research,the tensile, creep behavior and microstructure evolution of the as-cast K417 G superalloy under different conditions were investigated. The results exhibit that tensile cracks tend to initiate at MC carbide and γ/γ’ eutectic structure and then propagate along grain boundary. As the temperature for tensile tests increases from 21?C to 700?C, the yield strength and ultimate tensile strength of K417 G superalloy decreases slightly, while the elongation to failure decreases greatly because of the intermediate temperature embrittlement. When the temperature rises to 900?C, the yield strength and ultimate tensile strength would decrease significantly. The creep deformation mechanism varies under different testing conditions. At 760?C/645 MPa, the creep cracks initiate at MC carbides and γ/γ’ eutectic structures,and propagate transgranularly. While at 900?C/315 MPa and 950?C/235 MPa, the creep cracks initiate at grain boundary and propagate intergranularly. As the creep condition changes from 760?C/645 MPa to 900?C/315 MPa and 950?C/235 MPa, the ? phase starts to raft, which reduces the creep deformation resistance and increases the steady-state deformation rate.
关键词：
