形變誘導(dǎo)GH3625合金熱擠壓管材δ相的析出行為形變誘導(dǎo)GH3625合金熱擠壓管材δ相的析出行為PRECIPITATION BEHAVIOR OF δ PHASE OF DEFORMATION INDUCED GH3625 SUPERALLOY HOT-EXTRUDED TUBE 采用X射線衍射測定了GH3625合金熱擠壓管材在不同冷變形量下經(jīng)過800 ℃下時效后δ相的析出含量，并用掃描電子顯微鏡（SEM）、能譜分析（EDS）及Image-Pro Plus金相分析軟件等手段，研究了冷變形對δ相的析出規(guī)律及析出動力學(xué)的影響。結(jié)果表明，δ相首先在形變孿晶界、晶界以及變形帶上形核并析出，隨后在晶內(nèi)形核并長大，并且隨冷變形量的增加，δ相在變形帶上析出量增加；隨冷變形量的增加，δ相的形貌從針狀向棒狀或顆粒狀轉(zhuǎn)變；隨著時效時間的延長，δ相的平均尺寸不斷增大，并且長大規(guī)律符合LSW理論；當(dāng)時效溫度為800 ℃時，δ相的析出的含量與時效時間的關(guān)系滿足Avrami方程，且隨冷變形量的增加，δ相的含量增加，n值減小，α值增加，冷變形促進δ相的析出；Nb的溶質(zhì)拖曳與δ相的釘扎共同作用抑制晶粒長大，其合金的硬度隨保溫時間的延長ε=35 %時增加，ε≥50 %時未發(fā)生明顯變化。 The mass percentages of δ phase in GH3625 superalloy hot-extruded tube cold deformed to different reductions and then aged at 800℃ for different times were measured by the X-ray diffraction method. And through scanning electron microscopy (SEM), Energy Dispersive Spectrdmeter (EDS) and Image-Pro Pluse metallographic analysis software and other means. The effect of cold deformed on the law and kinetics of δ phase was precipitation investigated. The results show thatδ phase first precipitates at the deformation twin and grain boundaries and deformation bands, and then precipitates in the grains, and the amount of δ phase at the deformation bands increases with increasing cold deformation. The morphology of δ phase changes gradually from needles to spheroids or rodlike with increasing cold deformation. With the extend of aging time,the average size of δ phaseincreases, and the average size of δ phasegrows is in line with LSW theory. At 800℃, the relationship between the precipitation content of δ phase and aging time follows Avrami equation, as cold deformation increases, the content of δ phase increases, the value of n decreases, whereas the value of α increases. Cold deformation promotes the precipitation of δ phase. The solute drag of Nb in soild solution and pinning of δ phase inhibit the grain growth during aging process of cold deformed GH3625 superalloy hot-extruded tube. The hardness of the alloy increases with the extension of the holding time, ε = 35%, and ε≥50%, no obvious change occurs.
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