Primary creep behavior of Ti-48Al-2W as a function of stress and lamellar morphology
Primary creep behavior of Ti-48Al-2W as a function of stress and lamellar morphology
复制标题
Ti-48Al-2W 的初级蠕变行为与应力和层状形态的函数关系
DOI：
10.1007/s11661-003-0281-z
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
J. Beddoes
中科院分区：
文献类型：
--
作者：
D. Seo;L. Zhao;J. Beddoes
给出了粉末冶金 Ti-48Al-2W 从α区冷却到 1280 °C，然后空冷并在 950 °C 时效长达 96 小时后的全层状微观结构。时效时间短至 5 小时，可沿层状界面形成富含 W 的 β0 针状析出物，且 β0 尺寸随着时效时间的延长而增大。 β0 沉淀成核并在α2 片层中生长。同时，随着β0的形成，α2分解成不连续的片层。沿层状界面时效沉淀β0 会增加760 °C 拉伸强度（延展性略有降低）并降低瞬时蠕变应变，因为层状界面处的β0 沉淀会阻碍界面位错迁移率。 760℃、140~276MPa间断蠕变试验的变形微观结构表明，β0沿界面的析出显着降低了初级蠕变应变，这主要是由于β0对界面位错发射和运动的影响。这些结果从层状形态对瞬时蠕变应变和初级蠕变瞬态的影响进行了讨论，并强调了可能的蠕变机制。
The fully lamellar microstructure of powder metallurgy Ti-48Al-2W after cooling from theαregion to 1280 °C, followed by air cooling and aging at 950 °C for up to 96 hours, is presented. Aging times as short as 5 hours result in acicular-shaped precipitates of W-richβ0along lamellar interfaces, with theβ0size increasing with aging time. Theβ0precipitates nucleate and grow in theα2lamellae. Concurrently, with the formation ofβ0, theα2decomposes into discontinuous lamellae. Aging to precipitateβ0along lamellar interfaces increases the 760 °C tensile strength (with a slight reduction of ductility) and reduces the instantaneous creep strain, sinceβ0precipitates at lamellar interfaces hinder interface dislocation mobility. The deformed microstructures from interrupted creep tests at 140 to 276 MPa at 760 °C indicate that the precipitation ofβ0along interfaces substantially reduces the primary creep strain, primarily due to the influence ofβ0on interface dislocation emission and motion. These results are discussed in terms of the influence of lamellar morphology on the instantaneous creep strain and primary creep transient, and the possible creep mechanisms are highlighted.