Cyclic compressive creep-elastoplastic behaviors of in situ TiB₂/Al-reinforced composite

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• 作者：Qing Zhang^a ; Weizheng Zhang^a ; ^{zhangwz@bit.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Youyi Liu^b ; BingBin Guo^a
• 关键词：TiB2/Al-reinforced composite ; Cyclic coupled creep-elastoplasticity ; Micro mechanism ; Dislocations
• 刊名：Materials Science & Engineering A
• 出版年：2016
• 出版时间：1 June 2016
• 年：2016
• 卷：666
• 期：Complete
• 页码：1-9
• 全文大小：2191 K

文摘

This paper presents a study on the cyclic compressive creep-elastoplastic behaviors of a TiB₂-reinforced aluminum matrix composite (ZL109) at 350 °C and 200 °C. According to the experimental results, under cyclic elastoplasticity and cyclic coupled compressive creep-elastoplasticity, the coupled creep will cause changes in isotropic stress and kinematic stress. Isotropic stress decreases with coupled creep, leading to cyclic softening. Positive kinematic stress, however, increases with coupled creep, leading to cyclic hardening. Transmission electron microscopy (TEM) observations of samples under cyclic compressive creep-elastoplasticity with different temperatures and strain amplitudes indicate that more coupled creep contributes to more subgrain boundaries but fewer intracrystalline dislocations. Based on the macro tests and micro observations, the micro mechanism of compressive creep's influence on cyclic elastoplasticity is elucidated. Dislocations recovering with coupled creep leads to isotropic softening, whereas subgrain structures created by coupled creep lead to kinematic hardening during cyclic deformation.