Mn_(70)Fe_(30-x)Co_x(x=0,2,4)合金的组织和磁诱发应变

Microstructure and magnetic-field-induced strain in Mn_(70)Fe_(30-x)Co_x(x=0,2,4) alloys

采用真空非自耗电弧炉熔炼,然后进行固溶处理制备了Mn70Fe30-xCox(x=0,2,4)试样.运用X射线衍射分析、显微组织分析、差示扫描量热法(DSC)、标准电阻应变计法等实验方法,研究了添加Co对Mn-Fe合金的磁诱发应变(magnetic-field-induced strain,MFIS)性能的影响.研究表明,Mn70Fe30-xCox(x=0,2,4)试样在室温下为单一的γ相组织.随着Co含量的增加,Mn70Fe30-xCox(x=0,2,4)试样的磁性转变温度TN(Neel点)呈降低的趋势,但都高于室温,在室温下呈现反铁磁性;Mn70Fe30-xCox(x=0,2,4)试样的最大磁诱发应变也呈增加的趋势.Mn70Fe26Co4试样的MFIS在1.1T时达到60ppm.

Mn70Fe30-xCox （x=0, 2, 4） alloys were prepared using non-consumable vacuum arc furnace smelting followed by subsequently solution treatment. The effect of Co content on the property of magnetic-field-induced strain （MFIS） was studied by means of X-ray diffraction （XRD）, photomicrograph, differential scanning calorimetry （DSC）, and resistance strain gauge method. Result shows that Mn70Fe30-xCox （x=0, 2, 4） alloys are of singe phase γ at room temperature. With the increase of Co content, the Ne′el temperatures of alloys decrease, which are all higher than room temperature, i.e., the alloys exhibit antiferromagnetic austenite microstructure at room temperature after quenching from high temperatures. Alloys possess much larger MFIS with the increase of Co content, and taking Mn70Fe26Co4 as an example, when the magnetic field strength is 1.1 T, the MFIS is at its maximum, 6×10-5 .