Effect of grain size upon flow and fracture in a precipitation-strengthened Ti-8 wt % Al-0.25 wt % Si alloy
Effect of grain size upon flow and fracture in a precipitation-strengthened Ti-8 wt % Al-0.25 wt % Si alloy
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效果%20of%20grain%20size%20upon%20flow%20and%20fracture%20in%20a%20沉淀强化%20Ti-8%20wt%20%%20Al-0.25%20wt%20%%20Si%20合金
DOI：
10.1007/bf00708261
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发表时间：
1976
影响因子：
4.5
通讯作者：
J. Smith
中科院分区：
文献类型：
--
作者：
M. Mendiratta;S. Sastry;J. Smith
研究了Ti-8wt%Al-0.25wt%Si合金中晶粒度与析出强化的交互作用。合金在单μ相场中进行温热加工和退火处理后，可获得9~90αm的晶粒度。合金在两相(α-2)场中时效后，α基体中均匀分布着共格的α+α-2颗粒。有和没有α2析出物的合金的屈服强度霍尔-佩奇斜率几乎相等，表明析出物和晶界强化是线性相加的。当不含析出物的试件在所有晶粒度下都表现出较高的塑性时，含α2的试件的延伸率随着晶粒度的增大而急剧下降。含沉淀物的试样的电子显微镜观察显示出高度平面化的局部滑移，断口的扫描电子显微镜观察表明，随着晶粒度的增大，断裂行为从高度韧窝向混合解理和沿晶转变。
The interaction of grain size and precipitation strengthening has been studied in a Ti-8 wt % Al-0.25 wt %Si alloy. Grain sizes varying from 9 to 90μm were produced by warm-working and annealing the alloy in the single-α-phase field. A uniform distribution of the coherentα2particles in theαmatrix was produced by ageing the alloy in the two-phase (α+α2) field. The yield strength Hall-Petch slopes of the alloys with and without the α2precipitates were found to be nearly equal, indicating that the precipitation and grain-boundary strengthening are linearly additive. While specimens containing no precipitates exhibited a high ductility for all grain sizes, the ductility of the specimens with theα2particles decreased drastically with increasing grain size. TEM examination of the specimens containing the precipitates revealed a highly planar, localized slip and SEM examination of the fracture surfaces of these specimens revealed a transition in fracture behaviour from highly dimpled to mixed cleavage and intergranular with increasing grain size.