初始微结构对多晶金属Be宏观力学性能的影响  

Effect of Initial Microstructures on the Macroscopic Mechanical Properties of Polycrystalline Beryllium

作　　者：杨祖坤 张昌盛[1] 庞蓓蓓[1] 洪艳艳 莫方杰 刘昭 孙光爱[1] YANG Zukun;ZHANG Changsheng;PANG Beibei;HONG Yanyan;MO Fangjie;LIU Zhao;SUN Guang＇ai(Institute of Nuclear Physics and Chemistry,Chinese Academy of Engineering Physics,Mianyang 621999,China)

机构地区：[1]中国工程物理研究院核物理与化学研究所中国工程物理研究院中子物理学重点实验室,绵阳621999

出　　处：《金属学报》2018年第8期1150-1156,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51501170;国家重点研发计划项目No.2017YFB0702400;中国工程物理研究院院长基金项目No.2014-1-024~~

摘　　要：通过室温准静态(应变率10-3s-1)、高温准静态(600℃,应变率10-3s-1)和室温动态(应变率103s-1)预压缩变形分别实现金属Be内部3种不同微观结构的形成,进而实现多晶金属Be宏观压缩力学性能的调节,研究了初始微观结构对多晶金属Be压缩力学性能的影响及作用机理。结果表明,3种不同初始微结构样品中,室温准静态预压样品压缩力学响应最硬,而室温动态预压样品最软。显微组织、宏观织构测试以及原位中子衍射力学实验测试表明,室温准静态预压样品形成"弱织构"型初始微结构,微观力学响应上表现为(00.2)晶面优先受力,且由于引入一定位错使形变硬化效应相较于其它试样更为明显;而室温动态预压样品形成"强织构"型初始微结构且存在一些微孔洞,微观力学响应上表现为(00.2)晶面主要受力,微孔洞参与部分应力配分抑制了形变硬化效应;高温准静态预压样品形成的"随机取向"型初始微结构,微观力学响应上表现为初期各晶面均等受力、(11.0)晶面逐渐受力增加,且位错密度降低使内部协调变形相对容易。通过不同尺度上微观结构的协同配合可以实现宏观力学性能的调节,基于此可定制满足特定服役场景需求的性能。The hexagonal close-packed（hcp） metal Be has many potential applications. Much attention has been attracted on its mechanical properties and deformation mechanism. It has been found that the deformation mechanism involves the dislocation slip, twinning and their interaction, which are controlled by temperature, strain rate and initial texture. Typically, the softening and hardening behaviors in mechanical properties can be respectively induced through the elevated temperature and high strain rate. However, the microstructures engineering for properties tailoring in Be is still an open question. In this work, the effect of different initial microstructures on mechanical properties of polycrystalline beryllium was investigated, and the underlying mechanism was revealed by OM, SEM and in-situ neutron diffraction measurement. Three different kinds of microstructures have been achieved in Be by different predeformation strategies：（i） room temperature（RT） and the strain rate of 10-3 s-1,（ii） 600 ℃ and 10-3 s-1,and（iii） RT and 103 s-1, respectively. The mechanical properties of the polycrystalline Be are consequently tailored. The results show that, the compressive mechanical response is the hardest for the sample quasi-statically pre-deformed at RT, while is the softest for the dynamically pre-deformed one. The sample quasi-statically pre-deformed at RT possesses the ＂weak texture＂ type of initial microstructure, for which the（00.2） plane preferentially bears the compressive strain during the microscopic mechanical response; due to the combined effects of the initially preferred microstructure and induced dislocation, this sample exhibits the relatively obvious deformation-hardening with respect to the other ones. The sample dynamically pre-deformed at RT has the ＂strong texture＂ type of initial microstructure and some microvoids; the（00.2） plane also mainly bears the compressive strain during the microscopic response; however, the deformation-hardening effect is weakened because

关 键 词：多晶Be 初始微结构 压缩力学性能 原位中子衍射 

分 类 号：TG146.2[一般工业技术—材料科学与工程]