新型块体非晶合金Cu_(43)Zr_(43)Al_7Pd_7的形成能力及力学性能和腐蚀性能研究

STUDY OF FORMING ABILITY OF A NEW BULK METALLIC GLASS Cu_(43)Zr_(43)A1_7Pd_7 AND ITS MECHANICAL AND CORROSION PROPERTIES

利用铜模吸铸法成功制备了直径达5mm的新型块体非晶合金Cu_(43)Zr_(43)A1_7Pd_7．利用XRD,DSC,DTA研究了该合金的非晶形成能力(GFA)和热稳定性．结果表明,Cu_(43)Zr_(43)Al_7Pd_7表现出较好的非晶形成能力,表征非晶形成能力的参数T_(rg)和γ分别为0．61和0．417,过冷液相区△T_x达75K．单轴压缩实验和SEM断口观察表明,该合金具有良好的力学性能,材料压缩断裂应变量和断裂强度分别达到4．9%和1876 MPa．利用动电位极化研究了该非晶合金在1mol/L H_2SO_4和3%NaCl溶液中的电化学腐蚀行为．结果表明,非晶合金在这两种腐蚀介质中均存在自钝化现象,并形成较宽的稳定钝化区,钝化区电流密度在10^(-6)—10^(-5)A/cm^2间,远低于Cr18-Ni8不锈钢,表现出良好的耐蚀性能．

Cu43Zr43Al7Pd7 bulk metallic glass （BMG） with a diameter up to 5 mm was successfully prepared by copper mold casting method. The glass-forming ability （GFA） and thermal stability of the BMG obtained were investigated by means of XRD, DSC and DTA. It is shown that Cu43Zr43Al7Pd7 alloy exhibited an excellent glass forming ability, as indicated by high values of Trg （=0.61） and γ （=0.417） as well as wide a supercooled liquid region （△Tx=75 K）, respectively. Uniaxial compressive test and SEM fractography revealed that the BMG obtained possesses pretty good mechanical properties with an overall strain of 4.9% and a fracture strength of 1876 MPa, respectively. Electrochemical measurements were carried out in 1 mol/L H2SO4 and 3%NaCl aqueous solutions by potentiadynamic polarization at room temperature. The results showed that Cu43Zr43Al7Pd7 BMG exhibited spontaneous passivation in both solutions with wide passive regions. The passive current densities are about 10^-6—10^-5 A/cm^2, which are much lower than that of Cr18-Ni8 stainless steel, implying a good corrosion resistance.