摘要
采用Hopkinson拉杆技术和常规拉伸技术,在室温、5×10-4~800s-1应变速率范围内研究了具有复相(DP)和全片层(FL)组织的Ti-47%Al-1.5%Cr-0.5%Mn-2.8%Nb合金的拉伸力学性能.发现在高应变速率(动态)和低应变速率(静态)条件下两种组织都呈现出接近零塑性.DP组织的抗拉强度(σb)比FL组织的高,同种组织动态σb比静态的高.扫描电镜断口分析结果表明,两种组织的静态和动态的断裂方式基本相同,都是以穿晶解理为主,局部区域伴有沿晶开裂;TiAl合金的动态脆性和静态脆性一样,主要不是由环境因素造成.
A self designed Split Hopkinson tensile bar setup was used to investigate room temperature tensile properties of a γ TiAl alloy of Ti 47% Al 1.5% Cr 0.5% Mn 2.8% Nb with duplex (DP) and full lamellar (FL) microstructures at the strain rates between 70 and 800 s -1 . It is found that the alloy with either microstructure is extremely brittle at high strain rate, exhibiting near zero ductility. Its σ b is higher than that tested at a static strain rate of 5×10 -4 s -1 , and that the σ b of the DP material is higher than that of the FL material. Moreover, the former decreases while the latter increases with the increase of strain rate. Fractography analysis indicates that both materials fracture in a mixed mode of predominant transgranular cleavage and minor intergranular cracking, which is similar to the circumstances at static strain rates. Environmental effect did not appear to cause the room temperature brittleness of the alloy.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
1999年第2期165-169,共5页
Journal of Shanghai Jiaotong University
基金
国家自然科学基金
国家教委高温材料及高温测试开放实验室联合资助项目
关键词
力学性能
拉伸性能
钛合金
高应变速率
titanium aluminide
Seperated Hopkinson tensile bar (SHTB)
dynamic tensile properties