摘要
用热型连铸法以不同速度连铸了1.5mm的柱晶CuAlNi丝,检验其弯曲疲劳寿命。结果显示:固溶处理后消除了内应力,弯曲疲劳寿命随连铸速度的提高而提高,但超过480mm/min后由于出现等轴晶和加热后的晶粒长大,疲劳寿命下降。弯曲疲劳断裂首先从柱晶晶界开始开裂,然后各晶粒各自断裂。晶界开裂有利于阻隔疲劳裂纹扩展,降低对表面缺陷的敏感性,降低弯曲时在晶界上产生的应变量,从而提高疲劳寿命。
CuAINi wires of Ф1.5mm were cast by heated mold continuous casting process in different cast speeds to evaluate the bending fatigue performance. Results show that after removing internal stress by solid solution treatment at 900℃ ,the bending fatigue lifetime increases with the increase of cast speed, but decreases when cast speed exceeds 480mm/min. Rupture of bending fatigue begins from cracking of columnar grain boundaries.Then grains rupture independently. Boundaries＇ cracking tends to stop propagation of fatigue cracks, decrease sensitivity of fatigue to surface defects, and reduce bending strain rate exerting on the grains. These characteristics of columnar grain structure are beneficial to bending fatigue.
出处
《金属功能材料》
CAS
2006年第3期14-16,共3页
Metallic Functional Materials
关键词
热型连铸
CuAlNi
形状记忆合金
弯曲疲劳
heated mold continuous casting
CuAINi
shape memory alloy
bending fatigue
