Creep behaviour of an Al–8.5Fe–1.3V–1.7Si–15SiCp composite at temperatures ranging from 873 to 948 K
Creep behaviour of an Al–8.5Fe–1.3V–1.7Si–15SiCp composite at temperatures ranging from 873 to 948 K
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DOI：
10.1016/s0921-5093(01)01705-1
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发表时间：
2002-05
期刊：
影响因子：
6.4
通讯作者：
J. Čadek;K. Kuchařová;Shijie Zhu
中科院分区：
文献类型：
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作者：
J. Čadek;K. Kuchařová;Shijie Zhu
研究了15%（体积分数）Al-8.5Fe-1.3V-1.7Si合金的蠕变行为在873至948 K范围内的四个温度下研究了碳化硅颗粒-Al-8.5Fe-1.3Si-1.7Si-15 SiCp复合材料。用等温恒应力蠕变试验技术测定了最小蠕变应变速率ε。结果表明，真应力σ TH随温度升高近似线性下降，真应力指数n = 2.5，真蠕变激活能Δ HC与晶界扩散激活焓ΔHB接近。对于复合材料的蠕变行为，非常高的值和非常强的施加应力和温度依赖性的表观活化能Qc和表观应力指数mcare被发现是特征。这些值的Qc和mcare解释的真实阈值应力随温度的升高而降低。试图定性地解释真正的阈值应力的起源在晶界位错的行为和它们的相互作用与位于晶界的微粒和颗粒。
The creep behaviour of an Al–8.5Fe–1.3V–1.7Si alloy reinforced with 15 vol.% silicon carbide particles—an Al–8.5Fe–1.3Si–1.7Si–15SiCpcomposite—is investigated at four temperatures ranging from 873 to 948 K. The minimum creep strain rates ε ̇mare measured using the isothermal constant stress creep test technique. The results indicate the true threshold stress σTHdecreasing with increasing temperature approximately linearly, the true stress exponent n is found equal to 2.5, the true activation energy of creep ΔHcclose to the activation enthalpy of grain boundary diffusion ΔHB. For creep behaviour of the composite, very high values and very strong applied stress and temperature dependences of both the apparent activation energy Qcand the apparent stress exponent mcare found to be characteristic. These values of Qcand mcare interpreted in terms of the true threshold stress decreasing with increasing temperature. An attempt is made to account qualitatively for the origin of the true threshold stress in terms of behaviour of grain boundary dislocations and their interaction with particulates and particles located in grain boundaries.