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1、哈爾濱理工人學]二學碩一}:學位論文噴射成形GH742y鎳基高溫合金熱處理工藝研究摘要采用噴射成形技術(shù)制備的合金具有晶粒尺寸細小、過飽和固溶度和位錯密度高等特點,這就必然使得噴射成形合金的熱處理工藝與鑄錠冶金合金的熱處理工藝有所不同。因此深入研究噴射成形合金的熱處理工藝,對于進一步提高合金的使用性能具有重要意義。本文以熱等靜壓致密化后的噴射成形GH742y高溫合金為研究對象,對該合金的熱處理工藝做了比較系統(tǒng)的研究。利用光學顯微鏡和掃描電鏡(SEM)觀察了熱處理前后合金中y’相的形貌變化,分析了顯微
2、組織演變特點,從而初步優(yōu)化了該合金的熱處理工藝。利用固溶和時效硬化曲線以及力學性能實驗,進一步確定了優(yōu)化的熱處理工藝的合理性。結(jié)果表明,噴射成形高溫合金的組織為大小5嘰m左右的細小等軸晶,沉積態(tài)致密度為99.5%,熱等靜壓后合金晶粒并未明顯長大,致密度為99.6%。合金經(jīng)不同固溶工藝處理后,發(fā)現(xiàn)在1140℃固溶6h,空冷(AC)處理后,得到的】,,相尺寸細小、均勻,該固溶工藝為優(yōu)化的固溶工藝。合金經(jīng)固溶處理后,在不同時效條件下,時效硬化曲線在780℃/8h出現(xiàn)峰值。根據(jù)固溶和時效實驗,確定了兩種熱
3、處理工藝,分別為HTl:1140℃/8h(AC),HT::1140℃/8h(AC)+780"C/8h(AC)。室溫力學性能表明,均優(yōu)于傳統(tǒng)熱處理工藝的室溫性能,尤以HT2為好,這主要緣于HT2處理后合金中一次),’相、二次),,相的良好配合。從而確定噴射成形GH742y合金優(yōu)化的熱處理工藝為1140℃/6h+780℃/8h.AC。關(guān)鍵詞噴射成形;高溫合金;熱處理;顯微組織;力學性能哈爾濱理工人學工學碩f:學位論文StudyonHeatTreatmentProcessofSprayFormedGH7
4、42yNi-BaseSuperAlloyAbstractThemaincharacteristicsofsprayformedalloysarcveryfinemicrostructures,theextensionofsolidsolutionscomparedtotheconventionaltechniquessuchasingotmetallurgical.Itisnecessarythattheheattreatmentsprocessofsprayformedalloysshouldb
5、einfluencedbythesefeatures.Tofutureenhancethemechanicalpropertiesofthesprayformedalloys,itisimportanttostudydeeplytheheattreatmentproceduresofthesealloys.Theheattreatmentprocessesofthehotisostaticpressing(HIP)sprayformedGH742yalloywasstudiedinthepapef
6、.The),7phaseofalloyheattreatedwasobservedbyusingopticalmicroscopeandscanningelectronmicroscope(SEM),andpreliminaryoptimizetheheattreatmentprocess.T11evalidityoftheoptimumheattreatmentprocesswasprovedbyanalyzingthesolutionaginghardnessCurvesandmechanic
7、alproperties.Theresultsshownthemicrostmctureofthesprayformedalloyisfineequiaxedgrainswithabout5毗m,anddensityof95.5%foras.depositedalloy.ThegrainssizedidnotgrowsignificantlyafterHIPingconsolidatedtreatment,butthedensityofas-depositedalloyupto99.6%.Thef
8、ineanduniformy’phasewasobtainedat1140℃solutionfor6h,aircooling.Aftervariousagingtreatments,thepeakaginghardnessvaluereachedat780"C/8h,AC,accordingtotheaginghardnesscurves.Twoheattreatmentproceduresarcdeterminedaccordingtosolutionandageingtreat