(臺(tái)州學(xué)院 物理與電子工程學(xué)院，臺(tái)州 318000)
摘 要: 采用定向凝固方法制備了Ni47Mn32Ga21多晶合金，通過XRD譜和金相照片研究合金的結(jié)構(gòu)，通過對(duì)合金磁化強(qiáng)度與溫度關(guān)系、電阻與溫度關(guān)系、磁化曲線和磁感生應(yīng)變曲線的測(cè)量分析，研究了合金的相變、磁化特性及磁感生應(yīng)變特性。結(jié)果表明：Ni47Mn32Ga21合金在室溫(298K)時(shí)為四方結(jié)構(gòu)馬氏體相，晶格參數(shù)a=b=0.593 8 nm，c=0.553 1 nm。合金的馬氏體相變起始溫度Ms和終止溫度Mf分別為309 K和295 K，逆馬氏體相變起始溫度As與終止溫度Af 分別為306 K和319 K，居里溫度TC為365 K。室溫?zé)o壓力下，Ni47Mn32Ga21合金有較好的雙向可恢復(fù)磁感生應(yīng)變，其飽和磁感生應(yīng)變值達(dá)到−700×10−6。
關(guān)鍵字: Ni-Mn-Ga合金；定向凝固；馬氏體相變；形狀記憶合金；磁感生應(yīng)變
polycrystalline Ni47Mn32Ga21 directionally solidified alloy
（School of Physics and Electronic Engineering, Taizhou University, Taizhou 318000, China）
Abstract:Ni47Mn32Ga21 polycrystalline alloy was prepared by the directional solidification technique. The structure of the alloy were investigated using XRD and metallography methods. The phase-transformation, magnetization properties and magnetic-field-induced strains were also studied through analyzing the magnetization as a function of temperature, the resistance as a function of temperature, magnetization and magnetic field-induced strain curves. The results show that Ni47Mn32Ga21 alloy exhibits martensitic phase of a tetragonal structure with lattice parameters a=b=0.593 8 nm and c=0.553 1 nm at room temperature (298 K). The martensitic start temperature Ms and the martensitic finish temperature Mf are 310 K and 295 K, respectively. The austenitic start temperature As and austenitic finish temperature Af are 306 K and 319 K, respectively. The Curie temperature of alloy TC is 365 K. Ni47Mn32Ga21 alloy exhibits excellent free recoverability of the magnetic-field-induced strains at room temperature without external stress. The saturated value of magnetic-field-induced strain reaches −700×10−6.
Key words: Ni-Mn-Ga alloy; directional solidification; martensitic transformation; shape memory alloy; magnetic-field- induced strain
