固溶温度对一种高γ'相含量镍基高温合金显微组织和力学性能的影响
Effects of solid-solution temperature on heat-treated microstructure and mechanical properties of a novel nickel-base wrought superalloy with high γ'content
王广磊 1段然 1黄烁 1曲敬龙 1杜金辉 1赵光普1
作者信息
- 1. 北京钢研高纳科技股份有限公司,北京 100081;四川钢研高纳锻造有限责任公司,四川 德阳 618000
- 折叠
摘要
通过光学显微镜、场发射扫描显微镜和力学性能测试,研究了固溶温度对一种高γ'相含量镍基高温合金显微组织及拉伸、持久和高周疲劳性能的影响.结果表明:热轧变形组织在固溶过程中发生完全静态再结晶,再结晶晶粒在1120和1130℃时保持均匀细晶,在1150和1190℃时发生明显粗化且均匀性较差.随固溶温度升高,晶界一次γ'相含量逐渐降低,二次γ'相数量增加和尺寸降低,直至超过γ'相全溶温度(约1137.3℃).晶粒尺寸和晶内γ'相含量和分布共同决定合金的力学性能.室温和850℃拉伸强度随固溶温度升高先增大后减小,细晶组织的室温拉伸塑性较高,粗晶组织的850℃拉伸塑性稍微好.850℃/350MPa持久寿命受固溶温度的影响,再结晶晶粒越粗大,持久寿命越长,持久塑性越高.850℃高周疲劳寿命随固溶温度升高先缓慢增加后下降,经1130℃固溶的热处理组织具有较高的高周疲劳寿命.
Abstract
It was studied that the effects of solution temperature on heat-treated microstructure and resultant mechanical properties of a novel nickel based superalloy with a high content of γ'precipitates by means of optical microscopy(OM),field emission scanning electron microscopy(FE-SEM)and mechanical experiments.The as-received hot-rolled microstructure undergoes static recrystallization during the solid-solution treatment completely.The recrystallized grains remain fine uniformly at 1120 and 1130℃,but become significantly coarser with a poor uniformity at 1150 and 1190℃.As the solid-solution temperature rises,the content of primary γ'precipitates at grain boundaries decreases;while the number of secondary γ'precipitates increases and their size decreases,until it exceeds the γ'solvus(about 1134.3℃).It is indicated that the mechanical properties of this alloy are jointly determined by the size of γ grains and the content and distribution of γ'precipitates within γ grains.The tensile strength both at room temperature and 850℃increases first and then decreases with the increase of solid-solution temperature.Compared with that of coarse-grained microstructure,the tensile plasticity of fine-microstructure is high at room temperature but poor at 850℃.The coarser the recrystallized γ grains,the longer the stress-rupture lifetime and the higher the stress-rupture plasticity under 850℃/350MPa.The heat-treated microstructure with a solid-solution temperature of 1130℃obtains a higher high-cycle fatigue lifetime at 850℃.
关键词
镍基高温合金/高γ'相含量/固溶温度/显微组织/力学性能Key words
Ni-base wrought superalloy/high content of γ'precipitate/solid-solution temperature/microstructure/mechanical property引用本文复制引用
出版年
2024
NETL
NSTL
万方数据