GH4169合金激光沉积修复工艺研究
发布时间：2019-04-19 16:45
【摘要】：GH4169高温合金具有优秀的力学性能,在航空航天、核能发电和能源工业等行业得到广泛的应用。本文针对航空发动机上GH4169合金零件服役损伤后的快速修复需求,开展了对穿透性裂纹、沟槽类磨损的激光沉积修复工艺研究。研究了GH4169合金激光沉积态、预热修复及各热处理态修复试样的显微组织特征、应力消减和力学性能变化等情况。研究的主要成果如下:采用正交试验法优化GH4169合金激光沉积修复的工艺参数,得到无孔隙和熔合不良等缺陷的修复试样。沉积态修复组织特征为贯穿多层外延生长的柱状枝晶,枝晶之间有小角度转向,在枝晶间析出白色树枝状的连续Laves相,室温拉伸性能达到铸件标准。为改善GH4169合金沉积态试样性能的弱化,采用预热辅助激光沉积修复的方法,揭示预热工艺对修复组织和性能的影响规律。试验表明,当预热至300℃时,修复试样的枝晶组织变化不大,Laves相呈碎化的颗粒状,残余应力消减11.7%以上;拉伸强度与未预热试样基本一致,断后伸长率则提高到锻件标准Q/3B 548-1996(高强)的水平。揭示不同制度热处理工艺对修复试样组织、性能的变化规律。沉积态修复试样经不同时长的时效处理后,Laves相少量溶解,强度达到锻件标准,塑性略有下降;经固溶处理后,Laves相部分溶解,其周围析出大量针状δ相,强度达到锻件标准,断后伸长率提高21%;经均匀化处理后,Laves相基本溶解,在晶界及晶内均析出δ相,强度接近锻件标准,断后伸长率超过锻件标准27.1%。试验表明,合适的热处理可有效提高GH4169合金沉积态修复试样的强度与塑性。针对大型薄壁类工件在整体热处理中易变形、工装设计制造复杂等问题,提出基于感应加热的局部热处理方法。GH4169合金沉积态试样经局部时效热处理后,枝晶组织变化不大,Laves相出现部分溶解;残余应力平均降低33.5%以上,强度达到了锻件水平的86.8%以上。试验表明,局部感应热处理可实现大型薄壁类工件修复应力的消减。
[Abstract]:Because of its excellent mechanical properties, GH4169 superalloy has been widely used in aerospace, nuclear power generation and energy industry. In this paper, according to the requirement of rapid repair of GH4169 alloy parts in aero-engine after service damage, the laser deposition repair technology of penetrating cracks and groove-like wear is studied in this paper. The microstructure, stress reduction and mechanical properties of GH4169 alloy samples deposited by laser, preheated and repaired with various heat treatments were studied. The main results are as follows: the orthogonal test method was used to optimize the technological parameters of laser deposition repair of GH4169 alloy, and the repair samples without porosity and poor fusion were obtained. The deposited microstructure is characterized by columnar dendrites grown through multilayer epitaxial growth with small angle turn between dendrites and continuous Laves phase precipitating white dendrites between the dendrites. The tensile properties at room temperature are up to the standard of castings. In order to improve the weakening of the properties of deposited samples of GH4169 alloy, the influence of preheating technology on the microstructure and properties of the samples was revealed by using the method of preheating-assisted laser deposition. The results show that when preheated to 300 鈩，
本文编号：2461117
[Abstract]:Because of its excellent mechanical properties, GH4169 superalloy has been widely used in aerospace, nuclear power generation and energy industry. In this paper, according to the requirement of rapid repair of GH4169 alloy parts in aero-engine after service damage, the laser deposition repair technology of penetrating cracks and groove-like wear is studied in this paper. The microstructure, stress reduction and mechanical properties of GH4169 alloy samples deposited by laser, preheated and repaired with various heat treatments were studied. The main results are as follows: the orthogonal test method was used to optimize the technological parameters of laser deposition repair of GH4169 alloy, and the repair samples without porosity and poor fusion were obtained. The deposited microstructure is characterized by columnar dendrites grown through multilayer epitaxial growth with small angle turn between dendrites and continuous Laves phase precipitating white dendrites between the dendrites. The tensile properties at room temperature are up to the standard of castings. In order to improve the weakening of the properties of deposited samples of GH4169 alloy, the influence of preheating technology on the microstructure and properties of the samples was revealed by using the method of preheating-assisted laser deposition. The results show that when preheated to 300 鈩，
本文编号：2461117
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