【摘要】：GH4169高溫合金具有優(yōu)秀的力學(xué)性能,在航空航天、核能發(fā)電和能源工業(yè)等行業(yè)得到廣泛的應(yīng)用。本文針對航空發(fā)動機(jī)上GH4169合金零件服役損傷后的快速修復(fù)需求,開展了對穿透性裂紋、溝槽類磨損的激光沉積修復(fù)工藝研究。研究了GH4169合金激光沉積態(tài)、預(yù)熱修復(fù)及各熱處理態(tài)修復(fù)試樣的顯微組織特征、應(yīng)力消減和力學(xué)性能變化等情況。研究的主要成果如下:采用正交試驗(yàn)法優(yōu)化GH4169合金激光沉積修復(fù)的工藝參數(shù),得到無孔隙和熔合不良等缺陷的修復(fù)試樣。沉積態(tài)修復(fù)組織特征為貫穿多層外延生長的柱狀枝晶,枝晶之間有小角度轉(zhuǎn)向,在枝晶間析出白色樹枝狀的連續(xù)Laves相,室溫拉伸性能達(dá)到鑄件標(biāo)準(zhǔn)。為改善GH4169合金沉積態(tài)試樣性能的弱化,采用預(yù)熱輔助激光沉積修復(fù)的方法,揭示預(yù)熱工藝對修復(fù)組織和性能的影響規(guī)律。試驗(yàn)表明,當(dāng)預(yù)熱至300℃時,修復(fù)試樣的枝晶組織變化不大,Laves相呈碎化的顆粒狀,殘余應(yīng)力消減11.7%以上;拉伸強(qiáng)度與未預(yù)熱試樣基本一致,斷后伸長率則提高到鍛件標(biāo)準(zhǔn)Q/3B 548-1996(高強(qiáng))的水平。揭示不同制度熱處理工藝對修復(fù)試樣組織、性能的變化規(guī)律。沉積態(tài)修復(fù)試樣經(jīng)不同時長的時效處理后,Laves相少量溶解,強(qiáng)度達(dá)到鍛件標(biāo)準(zhǔn),塑性略有下降;經(jīng)固溶處理后,Laves相部分溶解,其周圍析出大量針狀δ相,強(qiáng)度達(dá)到鍛件標(biāo)準(zhǔn),斷后伸長率提高21%;經(jīng)均勻化處理后,Laves相基本溶解,在晶界及晶內(nèi)均析出δ相,強(qiáng)度接近鍛件標(biāo)準(zhǔn),斷后伸長率超過鍛件標(biāo)準(zhǔn)27.1%。試驗(yàn)表明,合適的熱處理可有效提高GH4169合金沉積態(tài)修復(fù)試樣的強(qiáng)度與塑性。針對大型薄壁類工件在整體熱處理中易變形、工裝設(shè)計制造復(fù)雜等問題,提出基于感應(yīng)加熱的局部熱處理方法。GH4169合金沉積態(tài)試樣經(jīng)局部時效熱處理后,枝晶組織變化不大,Laves相出現(xiàn)部分溶解;殘余應(yīng)力平均降低33.5%以上,強(qiáng)度達(dá)到了鍛件水平的86.8%以上。試驗(yàn)表明,局部感應(yīng)熱處理可實(shí)現(xiàn)大型薄壁類工件修復(fù)應(yīng)力的消減。
[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，

本文編號：2461117