Influence of microstructure on the Young's modulus in a Cu-2Be (wt%) alloy
Influence of microstructure on the Young's modulus in a Cu-2Be (wt%) alloy
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DOI：
10.1016/j.jallcom.2017.09.121
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发表时间：
2017-12
影响因子：
6.2
通讯作者：
S. Montecinos;S. Tognana;W. Salgueiro
中科院分区：
文献类型：
--
作者：
S. Montecinos;S. Tognana;W. Salgueiro
分析了Cu-2Be （wt%）合金显微组织对杨氏模量和硬度的影响。材料在1113 K下均质，在540 ~ 680 K的不同时间和温度下进行热时效。材料力学性能的改善，随着硬度和杨氏模量的增加，主要是由于在α基体中形成亚稳相。当温度高达623 K时，γ″析出相的形成使硬度在早期阶段增加。在676 K时，由于γ′相的存在，在0.75 h时达到最大硬度，并且进一步的时效时间会导致材料软化。杨氏模量曲线与硬度曲线表现出相似的行为。然而，在676 K时效超过1 h时，模量没有明显变化。那么，只有析出相的大小和形状对模量的值有影响，而取向的变化对模量的值没有影响。采用微观力学模型，根据E模量估算析出相的体积分数曲线。当时效温度为676 K，时效时间大于1 h时，由于析出相数量没有增加，且达到最大体积分数，模量基本保持不变。
The influence of microstructure on the Young's modulus and hardness in a Cu-2Be (wt%) alloy was analyzed. The material was homogenized at 1113 K and submitted to thermal aging at different times and temperatures between 540 and 680 K. The improvement of the mechanical properties of the material, with an increase of the hardness and Young's modulus is mainly due to the formation of metastable phases in the α matrix. For temperatures up to 623 K, the formation of γ″ precipitates produces an increase of the hardness in an early stage. At 676 K, the maximum hardness is reached for 0.75 h due to the presence of γ′ phase, and further aging times induce a softening of the material. The Young's modulus curves present a similar behavior respect to the hardness curves. However, no significant variation of the modulus was found for aging longer than 1 h at 676 K. Then, only the size and shape and not the change in the orientation of the precipitates would have influence on the value of the modulus. A micromechanical model was applied, and the volume fraction curves of precipitates were estimated from E modulus. For the aging temperature of 676 K and times longer than 1 h, the modulus is almost constant because there is no increase in the fraction of precipitates and their maximum volume fraction is reached.