| 引用本文: | 佘其海,李超,钟政烨.ECAP形变对高纯铝微结构及冲击层裂损伤的影响[J].材料科学与工艺,2020,28(4):48-56.DOI:10.11951/j.issn.1005-0299.20180393. |
| SHE Qihai,LI Chao,ZHONG Zhengye.Effect of ECAP deformation on microstructure and spall damage of high purity aluminum[J].Materials Science and Technology,2020,28(4):48-56.DOI:10.11951/j.issn.1005-0299.20180393. |
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| 摘要: |
| 在高应变率冲击载荷下,金属材料的主要失效方式之一是层裂损伤。为探讨微结构对层裂损伤的影响,本文利用等径角挤压(Equal Channel Angular Pressing,ECAP)技术制备了不同微结构的高纯铝,并对改性后的高纯铝进行平板撞击实验,通过电子背散射衍射表征加载后样品的孔洞分布和晶界取向差。研究发现:高纯铝在ECAP挤压变形过程中发生动态再结晶和动态回复,导致采用ECAP技术无法获得超细晶高纯铝；降低挤压温度可抑制动态再结晶,并得到尺寸相对较小的晶粒(约50 μm)。平板撞击实验结果表明,晶粒尺寸对弹性极限、层裂强度等宏观力学性能影响较小。回收样品分析表明,大晶粒样品中孔洞尺寸大而数量少,小晶粒样品中孔洞尺寸小,但数量多。孔洞在晶界(沿晶孔洞)及晶界附近(晶内孔洞)均可成核。晶内孔洞比沿晶孔洞数量多但尺寸小。大角度晶界比小角度晶界更容易导致沿晶孔洞成核,而晶内孔洞倾向于在45°～55°晶界附近成核。 |
| 关键词: 高纯铝 ECAP 微结构 晶粒尺寸 层裂损伤 晶界 晶界取向差 |
| DOI：10.11951/j.issn.1005-0299.20180393 |
| 分类号:TG146.2 |
| 文献标识码:A |
| 基金项目:国家重点研发计划项目(2017YFB0702002)；国家自然科学基金资助项目(11627901);四川省科技计划资助项目(2019YFG0445). |
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| Effect of ECAP deformation on microstructure and spall damage of high purity aluminum |
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SHE Qihai, LI Chao, ZHONG Zhengye
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(Key Laboratory for Advanced Technologies of Materials, Ministry of Education of China(Southwest Jiaotong University), Chengdu 610031, China)
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| Abstract: |
| Under high strain rate impact loads, one of the main failure modes of metallic materials is spall damage. In order to explore the effect of microstructure on spall damage, equal channel angular pressing (ECAP) technique is used to fabricate high purity Al with different microstructure. Planar impact spallation experiments are conducted on the as-ECAPed Al at different temperatures. The void distribution and grain boundary misorientation of the loaded samples were characterized by electron backscatter diffraction. Both dynamic recrystallization and dynamic recovery can occur in the ECAP process, which renders it difficult to obtain high purity Al with ultrafine grain using this technique. At low temperatures, dynamic recrystallization is suppressed, and relatively smaller grains with a size of ~50 μm can be obtained. The spall experiments were conducted on samples with two grain sizes. In the smaller grain sample, voids are larger in number but smaller in size, compared with voids in the larger grain sample. Voids tend to nucleate at a grain boundary or its vicinity, corresponding to intergranular voids and intragranular voids, respectively. Intragranular voids are smaller than intergranular voids. Intergranular voids prefer to nucleate at high-angle grain boundaries, while the grain boundaries with 45°～55°misorientation angles are preferred for intragranular voids. However, the grain size has a little effect on elastic limit and spall strength in this study. |
| Key words: high purity aluminum ECAP microstructure grain size spall damage grain boundary grain boundary misorientation |
