本文關(guān)鍵詞： 熔體過熱處理 GH4169 K418 F418 組織 力學(xué)性能　出處：《蘭州理工大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：熔體過熱處理影響合金的顯微結(jié)構(gòu),進而影響合金的力學(xué)性能。因此,本文選用X射線衍射儀、掃描電子顯微鏡和電子萬能試驗機等,對熔體過熱處理后GH4169、K418、返回料F418合金的顯微組織和力學(xué)性能的變化規(guī)律進行了研究,結(jié)果如下:熔體過熱處理后的GH4169合金,枝晶間Laves相、共晶γ+Laves和MC碳化物析出數(shù)量減少,分布均勻;Nb、Mo元素的偏析程度顯著降低;合金的室溫綜合力學(xué)性能提高。當感應(yīng)加熱功率為3.7KW時,抗拉強度有最大值721MPa,約是過熱處理前的1.5倍。合金熱處理后,析出γ″和脆性δ相,隨著熔體過熱溫度的升高,δ相溶解。當感應(yīng)加熱功率4.5KW時,合金的抗拉強度有最大值1079MPa,比熱處理前提高35.2%,同比,延伸率提高16.7%。K418合金經(jīng)固溶+時效熱處理后,隨著固溶溫度的逐漸升高,晶界上的碳化物由骨架狀向鏈狀轉(zhuǎn)變,γ′由不規(guī)則的棒狀向規(guī)則的立方形轉(zhuǎn)變,尺寸減小。存在最佳熱處理制度:1180℃×2h(AC)+930℃×16h(AC),合金的抗拉強度、延伸率和斷面收縮率均有最大值,分別為:821MPa、6.0%和5.7%。試樣斷口中心分布著枝晶林,沿二次枝晶根部斷裂,斷口外沿出現(xiàn)撕裂棱和韌窩,韌窩尺寸越小越密集,合金塑性越好。熔體過熱處理后的K418合金,γ′形貌變化不大,呈立方狀和不規(guī)則塊狀,MC碳化物由漢字骨架型轉(zhuǎn)變?yōu)殒湢�。合金的室溫綜合力學(xué)性能降低。當感應(yīng)加熱功率為44.5KW時,綜合力學(xué)性能最差,與過熱處理前相比,強度、延伸率和硬度分別降低約24%、50.9%和5.5%。熱處理后,初生碳化物MC與γ固溶體發(fā)生反應(yīng),生成γ′和細小粒狀或片狀的M6C/M23C6。當感應(yīng)加熱功率為40KW時,與熱處理前相比,合金的強度、延伸率和硬度分別降低約18.1%、43.4%和10.7%。復(fù)合熔鹽凈化+熔體過熱處理返回料F418合金后,γ′相尺寸增加,C、S、N元素含量降低,硬度降低。存在最佳過熱溫度1480℃,C、S、O、N元素含量均降低,與合金原始試樣成分相比,分別降低約51.9%、76.9%、5.6%和75.4%,同比,硬度降低約10.9%。
[Abstract]:The melt superheat treatment affects the microstructure of the alloy and then the mechanical properties of the alloy. Therefore, X-ray diffractometer, scanning electron microscope and electronic universal testing machine are used in this paper. The changes of microstructure and mechanical properties of F418 alloy after melt superheat treatment were studied. The results are as follows: the amount of precipitation of GH4169 alloy, interdendritic Laves phase, eutectic 緯 Laves and MC carbide after melt superheat treatment is reduced. The segregation degree of NbCMo element decreased significantly, and the comprehensive mechanical properties of the alloy at room temperature increased. When the induction heating power was 3.7 KW, the tensile strength reached a maximum value of 721 MPA, which was about 1.5 times that of that before superheat treatment. After heat treatment, the tensile strength of the alloy was 1.5 times that of that before superheat treatment. 緯 "and brittle 未 phase are precipitated, and the 未 phase dissolves with the increase of melt superheating temperature. When the induction heating power is 4.5 KW, the tensile strength of the alloy has a maximum value of 1079 MPA, which is 35.2% higher than that before heat treatment. With the increasing of the solution temperature, the carbides on grain boundaries change from skeleton to chain, 緯 'from irregular rod to regular square, and the size decreases. There is the best heat treatment system: 1: 1180 鈩，

本文編號：1506366