Mn元素对Fe-Ni-Co合金热膨胀性能影响

Thermal Expansion Properties of Fe-Ni-Co Super-Invar Alloy with Mn

研究了Mn对(Fe64Ni32Co4)1-xMnx(x=0,2.2,4.4,6.6(%,质量分数))合金物相、热膨胀性能影响,利用穆斯堡尔谱分析了合金内场分布及Mn对合金热膨胀性能的影响机制。结果表明,Mn促使合金生成FCC单相,增大其热膨胀系数。Mn含量较低时,穆斯堡尔谱为连续的铁磁六线谱迭加而成,当Mn含量增加到6.6%后则由顺磁单峰和铁磁六线谱迭加组成,Mn元素添加降低了合金中高自旋Fe原子数量,进而减弱升温过程中高自旋Fe原子向低自旋原子引起的体积缩小作用,是导致合金热膨胀系数增加的主要原因。

Investigation was made on the effect of Mn on both phase and thermal expansion properties of （Fe64Ni32Co4）1-xMnx（x=0,2.2,4.4,6.6（%, mass fraction） ） alloy. The hyperfine magnetic field distribution （HMFD） of alloys was measured by Mossbau-er spectra to study the influenced mechanism of Mn on the thermal expansion property. The results revealed that Mn added ahoy has single FCC phase, and the thermal expansion coefficient of alloys increased with increasing the Mn content. The mossbauer spectra ofthe alloys with low content Mn （x ≤ 4.4% ） were composed of ferromagnetic pattern, but it was composed of ferromagnetic and paramagnetic patterns when the Mn content was increased to 6.6%. The main reason for the increase of thermal expansion coefficient of （Fe64Ni32Co4）1-xMnx alloys is that the volume contraction effect in the process of high spin Fe atoms transfer to low spin Fe atoms with increasing temperature is weaken by the decrease of high spin Fe atoms with increasing the Mn content.