Ni_(45)Co_(5)Mn_(37.5−x)In_(12.5)Cr_(x)磁形状记忆合金相变和力学性能

Research on phase transformation and mechanical properties of Ni_(45)Co_(5)Mn_(37.5−x)In_(12.5)Cr_(x) magnetic shape memory alloys

采用电弧炉熔炼法制备了Ni_(45)Co_(5)Mn_(37.5−x)In_(12.5)Cr_(x)合金铸锭,研究了用Cr部分替代Mn对Ni_(45)Co_(5)Mn_(37.5)In_(12.5)磁性形状记忆合金的显微组织、马氏体相变、力学性能的影响。结果表明,由于价电子浓度的减小,Cr替代Mn使得马氏体相变温度明显降低,随着Cr替代量增大,马氏体结构从单斜14M结构转变为10M结构,在Cr替代量较高的合金中观察到颗粒状和长条状富Cr析出物。替代量x=3的样品,其颗粒状和长条状析出物在合金内部均匀分布,未掺杂合金的抗压强度为130 MPa,而x=3的合金抗压强度达到了881 MPa,压缩实验表明掺杂Cr元素能显著提高Ni-Co-Mn-In合金的力学性能。

Ni_(45)Co_(5)Mn_(37.5−x)In_(12.5)Cr_(x) alloy ingots were prepared by arc furnace melting.The effects of partial substitution of Cr for Mn on microstructure,martensitic transformation and mechanical properties of Ni_(45)Co_(5)Mn_(37.5−x)In_(12.5)Cr_(x) magnetic shape memory alloy were investigated.The results show that with the decrease of valence electron concentration,substitution of Cr for Mn results in obvious temperature decreases in martensitic transformation.With the increase of Cr content,the martensitic structure changes from monoclinic 14M to 10M.Cr-rich precipitates are observed in the alloy with higher Cr content,in which the precipitates are granular and long strip.The compressive strength of the undoped alloy is 130 MPa,while the compressive strength of the alloy doped with 3 at%Cr reaches 881 MPa.The compression test shows that the mechanical properties of Ni-Co-Mn-In alloy can be significantly improved by droping Cr.