摘要
以固溶—时效和固溶—大变形(压缩、ECAP)—时效加工的7085铝合金为实验对象,分别采用拉伸试验机、X射线衍射仪(XRD)和晶体微区取向分析技术(EBSD)对7085铝合金的拉伸性能、内部的位错密度、单元边界(小角度晶界)和晶粒边界(大角度晶界)进行研究,结合拉伸试验测得的屈服强度,定量计算强化项对不同状态下铝合金的强化贡献。结果表明,相比常规固溶—时效工艺,固溶—大变形—时效工艺加工的7085铝合金的拉伸强度从381.2MPa分别提升到475.6和543.3 MPa;位错强化显著提高,从零分别提高到107.4和180.6 MPa;小角度强化显著提高,从10.4 MPa分别提高到89.1和116.4 MPa。7085铝合金强度提高来源于材料内部的位错和小角度晶界;固溶后的大变形加速了时效,降低了时效沉淀强化。并且发现强烈塑性变形加工(ECAP)的强化效果高于传统塑性变形加工(压缩变形)的效果。
High-strength 7085 aluminum alloy was prepared by conventional solution-aging and solution-large deformation-aging, separately; wherein, large deformation included compression and ECAP （equal channel angular pressing）. The tensile properties, internal dislocation density, unit boundary （small-angle grain boundaries） and grain boundaries （high-angle grain boundaries） of 7085 aluminum alloy were investigated by a tensile testing machine, X-ray diffraction （XRD） and electron back scattering diffractions （EBSD）. Combined with the yield strength measured by tensile tests, the contribution of strengthening items to strengthening of the alloy in different states was calculated quantitatively. Results show that the tensile strength of the 7085 alloy by solution-compression-aging and solution-ECAP-aging upgrades from 381.2 MPa of the conventional solid solution-aging process to 475.6 MPa and 543.3 MPa, respectively; their dislocation strengthening also significantly increases from zero to 107.4 MPa and 180.6 MPa, respectively; besides, small angle strengthening greatly increases from 10.4 MPa to 89.1 MPa and 116.4 MPa, respectively. Higher strength of 7085 aluminum alloy arises from the internal dislocations and small-angle grain boundaries. Large deformation after solution accelerates aging and reduces the aging precipitation hardening. The strengthening effect of strong plastic deformation （ECAP） is better than that of the traditional plastic deformation （compression）.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2017年第4期1008-1012,共5页
Rare Metal Materials and Engineering
基金
国家自然科学资金(51074079)
江苏省高校科研成果产业化推进项目(JH10-37)
江苏大学"拔尖人才培养工程"基金(1211110001)
关键词
7085铝合金
大变形
屈服强度
位错强化
小角度强化
7085 aluminum alloy
large deformation
yield strength
dislocation strengthening
small-angle grain strengthening
