论文标题
通过微柱压缩测试对沉淀类型对Al-CU合金机械行为的影响分析
An analysis of the influence of the precipitate type on the mechanical behavior of Al-Cu alloys by means of micropillar compression tests
论文作者
论文摘要
不同类型的沉淀物（Guinier -Preston区域，$θ''$或$θ'$）对临界分辨剪应力和应变硬化的影响是通过Al -4 wt中的微骨压缩测试确定的。 \％cu合金。在每种情况下测量沉淀物的大小，形状和体积分数。人们发现，直径$ \ ge $ 5 $μ$ m的微柱的尺寸效果可以忽略不计。带有豚鼠的微柱子由于沉淀剪切而显示出应变定位。最佳的机械性能是通过$θ''$沉淀物或$θ'$的精细分散体获得的。在$θ''$沉淀物周围观察到沉淀的剪切和Orowan环，并且微柱强度与Orowan模型的预测兼容。对于具有$θ'$沉淀物的合金，必须在模型中包括与沉淀物周围的转化应变相关的加强贡献，以解释实验结果。最后，使用不同方向的晶体中的微柱压缩试验来校准现象学晶体可塑性。该信息用于通过计算均匀化来预测多晶的机械性能。
The influence of different types of precipitates (either Guinier-Preston zones, $θ''$ or $θ'$) on the critical resolved shear stress and strain hardening was determined by means of micropillar compression tests in an Al - 4 wt. \% Cu alloy. The size, shape and volume fraction of the precipitates were measured in each case. It was found that size effects were negligible for micropillars with diameter $\ge$ 5 $μ$m. Micropillars with Guinier-Preston zones showed strain localization due to precipitate shearing. The best mechanical properties were obtained with either a fine dispersion of the $θ''$ precipitates or a coarser dispersion of $θ'$. Both precipitate shearing and Orowan loops were observed around the $θ''$ precipitates and the micropillar strength was compatible with the predictions of the Orowan model. In the case of the alloy with $θ'$ precipitates, the strengthening contribution associated with the transformation strain around the precipitates has to be included in the model to explain the experimental results. Finally, the micropillar compression tests in crystals with different orientations were used to calibrate a phenomenological crystal plasticity. This information was used to predict the mechanical properties of polycrystals by means of computational homogeneization.
