合金钢的高温单轴棘轮效应实验研究1.25Cr0.5Mo

Ratcheting behavior of 1.25Cr0.5Mo alloy under uniaxial loading at elevated temperatures

利用MTS810电液伺服试验机在300℃温度下对1.25Cr0.5Mo合金钢进行了单轴棘轮效应实验研究,探讨了温度、应力幅值、应力峰值、平均应力以及加载历史对材料棘轮效应的影响.以0.1%/s及0.2%/s两种不同的应变加载速率分别对材料进行单轴拉伸实验,结果表明1.25Cr0.5Mo合金钢在所研究的温度范围内的变形行为是率无关的;在0.4%应变幅值下进行了单轴应变循环实验,响应应力幅值随循环次数几乎没有变化,可视为循环稳定材料;单轴棘轮效应实验表明棘轮应变速率随平均应力、应力幅值及温度的升高而增大;棘轮变形依赖于加载历史,先前较大的循环应力对后继较小的循环应力下的棘轮变形起抑制作用.

A series ofuniaxial ratcheting tests for 1.25Cr0.5Mo alloy were carried out by MTS810 electro-hydraulic servo tester at 300℃. And the effects of temperature, cyclic stress amplitude, peak stress and mean value, ratcheting history on the ratcheting behavior of 1.25Cr0.5Mo alloy were investigated. Monotonic tensile tests at two different strain loading rate （0.1%/s and 0.2%/s） revealed that the deformation behaviors of 1.25Cr0.5Mo alloy in the temperature range of study are rate-independent. Uniaxial strain circulating test was conducted with the strain amplitude 0.4%, the response stress amplitude kept almost unchanging with cyclic number, which indicated circulation stabilization. Uniaxial ratcheting tests showed that the ratcheting strain increased with the increase of applied mean stress, stress amplitude and temperature. Ratchet deformation was dependent upon loading history, previously large cyclic stress on subsequent smaller cyclic stress deformation under ratchet uo the inhibition.