摘要
采用扫描电镜和X射线衍射方法研究了添加微量Dy元素(0～0.1%(质量分数))对Ni-44Ti-6Al合金微观组织的影响,并采用力学压缩实验研究了合金的室温和高温力学性能。结果表明,Dy元素在Ni-44Ti-6Al合金中的NiTi基体相中固溶,但其固溶度仅为0.03%(原子分数),同时使晶粒细化。超量的Dy以氧化物的形式析出,大部分呈颗粒状分布在晶界。适量的Dy能够有效提高合金的室温屈服强度和塑性。添加0.05%Dy的合金的屈服强度和塑性变形率均达到最大值,分别为1570 MPa和10.9%;Dy含量继续增加,合金的屈服强度和塑性变形率有所下降。Dy能够显著提高合金在600～800℃下的屈服强度,添加0.05%Dy合金的屈服强度最高。Dy对合金力学性能的改善主要归因于晶粒细化和固溶强化作用。
The effects of Dy addition on the microstructure Ni-44Ti-6A1 alloy were studied through electron scanning electron micros- copy （SEM） and X-ray diffraction （XRD） measurements, and the mechanical properties of Ni-Ti-A1-Dy alloys were investigated by compressive tests at room temperature and elevated temperatures. The results showed that Dy existed as a solid solution element in NiTi phase in Ni-44Ti-6A1 alloy with the small solubility of 0.03% （mass fraction）, and, moreover, caused the refinement of crystal grains. The extra Dy tended to form Dy-O phase, distributing as small particles in gain boundaries. The yield stress and plasticity of Ni-d.4Ti- 6A1 alloy were improved by the addition of Dy. For Ni-44Ti-6A1 alloy with Dy of 0.05%, the yield stress and plasticity reached the maximum values of 1570 MPa and 10.9% , respectively, but the corresponding values decreased with further increase of Dy content. The yield strength of Ni-44Ti-6Al alloy at 600 - 800 ℃ was remarkably increased by the addition of Dy and it exhibited the maximum value when Dy content was 0.05%. The improvement of mechanical properties was mainly attributed to the grain refinement and solid solution strengthening effects caused by Dy.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2013年第2期171-178,共8页
Chinese Journal of Rare Metals
基金
国家自然科学基金(50501001)
教育部新世纪优秀人才计划项目(NCET-09-0024)资助
