熔体快淬对Ni-Mn-Ga合金马氏体相变特征及应变的影响

用真空快淬炉制备了名义成分为Ni₅₀Mn₂₇Ga₂₃，淬速 分别为2，4，8m/s的快淬态试样，并将部分试样热处理.研究结果表明，与铸态相比，快淬态试样马氏体相 变温度、居里温度均有所降低，经热处理后，降低的马氏体温度和居里温度会提高.快淬合 金与铸态合金相比更容易获得单相的Ni₂MnGa结构，并能使合金主衍射峰从（22 0）转向（ 400），形成织构，热处理后织构消失.快淬工艺对相变应变和磁致应变的影响表现出复杂性 ，研究发现获得织构的快淬带具有较浇铸态试样更大的相变应变和磁致应变. 关键词： 50Mn₂₇Ga₂₃')" href="#">Ni₅₀Mn₂₇Ga₂₃ 快淬 马氏体相变 应变

The effect of rapid quenching from melt on Martensitic transition and strain cha racteristics of Ni-Mn-Ga alloy

Ni₅₀Mn₂₇Ga_{23/sub> alloy was prepared by melt_spinning at wheel velocities of 2,4 and 8m/s separately. The experimental results showed that the rapid quenching caused the decrease of the martensitic transformation temperature an d Curie temperature, while subsequent annealing would increase the depressed val ues. The NiMnGa specimens with a single_phase structure could be obtained more e asily in melt_spun ribbons than in cast alloys. Furthermore, x_ray diffraction s tudies revealed that the main diffraction peak drifted from (220) to (400) in me lt_spun ribbons, which made the texture form, and subsequent annealing made it d isappear. The effects of rapid quenching on the phase_transition strain and magn etic field_induced strain are very complicated. It was found that the phase tran sition strain and magnetic field_induced strain of melt_spun ribbons with textur e were larger than that of cast specimens.}