發(fā)布時間：2019-01-11 13:01

【摘要】：本文研究了經(jīng)δ相時效處理(DP)后的Inconel 718合金中δ相在不同熱處理制度時的溶解行為,利用光學(xué)顯微鏡分析了不同溫度和保溫時間下δ相含量和晶粒尺寸變化,獲得了δ相在靜態(tài)溶解過程中的演變規(guī)律：采取硬度測試方法表征了溶解過程中δ相含量變化與其硬度數(shù)值之間的相互規(guī)律；使用Deform數(shù)值模擬軟件預(yù)測了靜態(tài)溶解過程中合金晶粒尺寸的變化規(guī)律,進(jìn)而與實(shí)際實(shí)驗(yàn)結(jié)果相對比,可為Inconel 718 DP工藝的制定提供理論依據(jù)。研究結(jié)果表明,DP處理的Inconel 718合金在熱處理過程中針狀δ相在溶解過程中的形貌特征變化可分為兩個階段,初期的變化主要表現(xiàn)為長針狀δ相溶解成為短針狀乃至球狀,后期的溶解過程主要是短針狀δ相溶解成球狀及部分球狀δ相尺寸的減小。不同的熱處理溫度下,隨著保溫時間的延長,δ相的溶解量與保溫時間的關(guān)系由溶解初期的線性關(guān)系變?yōu)槿芙夂蟮慕茠佄锞�關(guān)系,溶解速度逐漸降低；在950℃、980℃和1000℃時,δ相的溶解量在保溫一段時間后達(dá)到穩(wěn)定值,而在溫度為1020℃和1060℃時,δ相可持續(xù)溶解,最終完全溶解；溶解初期δ相體積分?jǐn)?shù)的迅速降低是界面反應(yīng)起主要作用,溶解后期主要是受擴(kuò)散過程控制。δ相溶解過程中Inconel 718合金硬度測試結(jié)果表明,在同一溫度下,隨著保溫時間的延長,合金的硬度值不斷的降低；在相同保溫時間下,熱處理溫度越高,合金的硬度越低。在溶解初期,合金硬度值下降的比較快,溶解后期合金硬度慢慢的趨于一個穩(wěn)定值；DP處理工藝相比固溶處理工藝,通過增加合金中6相的含量來提高合金的硬度。DP處理Inconel 718合金δ相溶解過程中晶粒尺寸變化規(guī)律及數(shù)值模擬結(jié)果表明,當(dāng)保溫時間一定時,隨著熱處理溫度的升高,晶粒尺寸長大越明顯；當(dāng)保溫溫度一定時,隨著保溫時間的延長,晶�？焖俚拈L大,晶粒長大成拋物線規(guī)律變化,平均晶粒尺寸明顯增加,隨著保溫時間的繼續(xù)增長,晶粒長大的速度變慢,依據(jù)試驗(yàn)統(tǒng)計(jì)數(shù)據(jù),建立了δ相時效態(tài)Inconel 718合金熱處理過程晶粒尺寸長大模型；δ相溶解過程中晶粒尺寸預(yù)測結(jié)果與實(shí)驗(yàn)結(jié)果最大誤差為4.2%,說明所建立的模型能夠較好地用于描述Inconel 718合金DP處理后δ相溶解過程中的平均晶粒尺寸變化規(guī)律。
[Abstract]:In this paper, the dissolution behavior of 未 phase in Inconel 718 alloy treated with 未 phase aging under different heat treatment conditions was studied. The changes of 未 phase content and grain size at different temperature and holding time were analyzed by optical microscope. The evolution law of 未 phase in the static dissolution process is obtained. The mutual law between the content change of 未 phase and its hardness value during the dissolution process is characterized by hardness test method. Deform numerical simulation software was used to predict the grain size change of the alloy during static dissolution. Compared with the experimental results, it can provide a theoretical basis for the formulation of Inconel 718 DP process. The results show that the morphology of needle-like 未 phase in Inconel 718 alloy treated with DP during heat treatment can be divided into two stages. The main changes in initial stage are that the long needle-like 未 phase dissolves into short acicular phase and even globular phase. The dissolution process in the later stage is mainly due to the reduction of the size of the spherical and partial spherical 未 phases in the short needle-like 未 phase. At different heat treatment temperatures, with the prolongation of the holding time, the relationship between the dissolution amount of 未 phase and the holding time changes from the linear relationship at the initial stage of dissolution to the approximate parabola relationship after dissolution, and the dissolution rate decreases gradually. At 950 鈩，

本文編號：2407166