【摘要】：為了揭示14H相的形成機(jī)理,制備并研究了18R LPSO單相Mg-Y-Zn(簡(jiǎn)稱S18)合金經(jīng)773 K退火100 h的顯微組織演變。結(jié)果表明:鑄態(tài)S18合金主要由18R相組成(其體積分?jǐn)?shù)高于93%),并含有少量的W相和α-Mg相。退火時(shí),S18合金中的18R相保持穩(wěn)定,未轉(zhuǎn)變成14H LPSO結(jié)構(gòu)。然而,在α-Mg相內(nèi)部形成了14H層片相,其尺寸和體積分?jǐn)?shù)隨著退火時(shí)間的延長(zhǎng)不斷增大。TEM分析表明,14H相在α-Mg內(nèi)基面堆垛層錯(cuò)區(qū)域獨(dú)立形核。14H層片的增厚生長(zhǎng)是界面控制過(guò)程,與基面臺(tái)階的形成密切聯(lián)系。而14H層片的伸長(zhǎng)生長(zhǎng)屬于擴(kuò)散控制,與溶質(zhì)元素的擴(kuò)散有關(guān)。該18R單相合金中14H相的形成機(jī)理可通過(guò)反應(yīng)式α-Mg'→α-Mg+14H表示。
[Abstract]:In order to reveal the formation mechanism of 14H phase, the microstructure evolution of 18R LPSO single-phase Mg-Y-Zn (S18) alloy annealed at 773K for 100h was investigated. The results show that the as-cast S18 alloy mainly consists of 18R phase (volume fraction > 93%) and contains a small amount of W phase and 偽 -Mg phase. During annealing, the 18R phase in S18 alloy remained stable and did not change into 14H LPSO structure. However, a 14H lamellar phase was formed in the 偽 -Mg phase. The size and volume fraction of the 14H phase increased with the annealing time. Tem analysis showed that the thickening growth of the 14H phase in the stacking fault zone of 偽 -Mg was a process controlled by the interface. It is closely related to the formation of base steps. The elongation growth of 14H laminates is controlled by diffusion, which is related to the diffusion of solute elements. The formation mechanism of 14H phase in the 18R single phase alloy can be expressed by the reaction formula 偽 -Mg'n 偽 -Mg 14H.
【作者單位】： 河海大學(xué)力學(xué)與材料學(xué)院;河海大學(xué)海洋與近海工程研究院;揚(yáng)州大學(xué)機(jī)械工程學(xué)院;東南大學(xué)材料科學(xué)與工程學(xué)院;
【基金】：Project(BK20160869)supported by the Natural Science Foundation of Jiangsu Province,China Project(GY12015009)supported by the Nantong Science and Technology Program,China Project(2015B01314)supported by the Fundamental Research Funds for the Central Universities,China Project(51501039)supported by the National Natural Science Foundation of China
【分類號(hào)】：TG146.22;TG166.4

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