(中南林業(yè)科技大學 機電工程學院，長沙 410004)
摘 要: 基于擠壓態(tài)FGH4096合金雙圓錐臺試樣熱壓縮變形及過固溶熱處理試驗，結(jié)合DEFORM有限元軟件數(shù)值模擬，確定試樣中各等效應變范圍內(nèi)臨界晶粒長大分布規(guī)律，研究熱加工工藝對擠壓態(tài)FGH4096合金臨界晶粒長大的影響。結(jié)果表明：在溫度980~1060 ℃、應變速率0.003~0.03 s-1條件下，雙圓錐臺試樣熱變形后再經(jīng)過固溶熱處理，合金臨界晶粒長大的窗口條件從低溫低應變速率向高溫高應變速率轉(zhuǎn)變，其中(980 ℃、0.03 s-1)、(1060 ℃、0.003 s-1)條件下可以避免出現(xiàn)臨界晶粒長大，并獲得均勻晶粒組織。當變形溫度為980 ℃時，隨著應變速率的增加，異常晶粒長大程度減小，且合金臨界晶粒長大位置的臨界等效應變數(shù)值降低；當應變速率為0.03 s-1時，隨著變形溫度的升高，異常晶粒長大程度增大，且試樣發(fā)生臨界晶粒長大的等效應變區(qū)域擴大。
關鍵字: FGH4096合金；擠壓態(tài)；熱壓縮；過固溶熱處理；臨界晶粒長大
（College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, China）
Abstract:Based on the hot compression deformation and supersolvus heat treatment of extruded FGH4096 alloy double-cone specimens, with the DEFORM numerical simulation, the distribution of critical grain growth (CGG) in different effective strain ranges was determined. The effect of hot working process on CGG of extruded FGH4096 alloy was studied. The results show that the window conditions for the CGG of the alloy range change from low strain rate at low temperature to high strain rate at high temperature, after the double-cone specimens deformed at temperature of 980-1060 ℃ and strain rate of 0.003-0.03 s-1 and treated by supersolvus heat treatment. Then the CGG can be avoided and uniform grain structure can be obtained at (980 ℃, 0.03 s-1) and (1060 ℃, 0.003 s-1).With the increase of strain rate, the degree of abnormal grain growth and the critical effective strain of CGG decreases at 980 ℃. On the other hand, with the increase of deformation temperature, the degree of abnormal grain growth increases and the effective strain region of CGG enlarges at strain rate of 0.03 s-1.
Key words: FGH4096 superalloy; hot extrusion; thermal compression; supersolvus heat treatment; critical grain growth
