楊哲人2006-07-252018-06-282006-07-252018-06-282004http://ntur.lib.ntu.edu.tw//handle/246246/12480雙相不銹鋼兼具沃斯田鐵系不銹鋼之耐 蝕性與韌性及肥粒鐵系不銹鋼之強度與耐應 力腐蝕性，廣泛應用於化學、石油、能源等 工業。本研究係探討2205 雙相不銹鋼在低溫 時效的脆性及相變態。實驗結果顯示：雙相 不銹鋼在475 ℃ 時效對於脆性有最大的效 應;此時效脆性機構與肥粒鐵系不銹鋼之低 溫時效脆性類似;高溫肥粒鐵相於475 ℃ 時 效，產生離相分解相變態，分解成微細的富 鐵相(α)及富鉻相(α΄)，形成不規則形狀且 內部互相連接的網狀結構，差排於此結構中 互相交錯不易移動，導致材料嚴重的脆性。The effect of isothermal treatment (at temperatures ranging between 400 and 500℃) on the embrittlement of a 2205 duplex stainless steel (with 45 ferrite–55 austenite, vol%) has been investigated. The impact toughness and hardness of the aged specimens were measured, while the corresponding fractography was studied. The results show that the steel is susceptible to severe embrittlement when exposed at 475 ℃; this aging embrittlement is analogous with that of the ferritic stainless steels, which is ascribed to the degenerated susceptible to severe embrittlement when exposed at 475 ℃; this aging embrittlement is analogous with that of the ferritic stainless steels, which is ascribed to the degenerated ferrite phase. High-resolution transmission electron microscopy reveals that an isotropic spinodal decomposition occurred during aging at 475 ℃ in the steel studied; the original δ-ferrite decomposed into a nanometer-scaled modulated structure with a complex interconnected network, which contained an iron-rich BCC phase (α) and a chromium-enriched BCC phase (α΄). It is suggested that the locking of dislocations in the modulated structure leads to the severe embrittlement.application/pdf6507760 bytesapplication/pdfzh-TW國立臺灣大學材料科學與工程學研究所雙相不銹鋼脆性衝擊韌性硬度離相分解Duplex stainless steelEmbrittlementImpact toughnessHardnessSpinodal decompositionreporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/12480/1/922216E002031.pdf