稀土元素对钯的力学性能的影响

Influence of Rare-Earth Elements on Mechanical Properties of Palladium

研究了０．１～０．６ａｔ％ＲＥ元素对Ｐｄ的力学性能的影响。稀土不仅提高Ｐｄ的室温强度和弹性模量，也提高Ｐｄ的高温瞬时强度、蠕变寿命和激活能以及Ｐｄ的延伸率。在稀浓度范围内，强度性质随浓度呈线性增高。按０．１ａｔ％ＲＥ归一化处理ＰｄＲＥ合金强度性质，发现轻稀土元素对强度性质的影响高于重稀土元素，而Ｅｕ、Ｙｂ、Ｃｅ对强度性质有反常的影响：在所有Ｐｄ－ＲＥ合金中，Ｐｄ－Ｅｕ合金有最高的强度性质，其次为Ｐｄ－Ｙｂ和Ｐｄ－Ｃｅ合金。稀土在合金中的作用机制，如净化杂质，提高再结晶温度，细化晶粒，膨胀晶格，提高原子间结合力，增大位错密度与降低堆垛层错层，通过内氧化形成稳定稀土氧化物等被观察到了。它们对Ｐｄ－ＲＥ合金的强度性质和高延伸率作出了贡献。

The influence of 0.1～0.6at%RE additions(RE = La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Er,Yb)on the mechanical properties of Pd wasstudied.All above RE additions increased not noly the strength properties atambient temperature but also the tensile strength,creep ruptature time andactivation energy at high temperature,simultaneously increased the elongationof Pd.In the range of dilute concentration,the strength properties of Pd-REalloy enhanced linearly with RE concentration. When the strength propertiesof Pd-RE alloys were normalized on 0.1at%RE,it was found that light REelements have stronger effect on the properties of Pd than heavy RE,WhereasEu,Yb,Ce have anomalus effect.In all Pd-RE alloys,Pd-Eu alloys have thehighest strength properties,successively Pd-Yb and Pd-Ce alloys.The effectmechanisms of RE in alloy,such as purifying impurities,increasing recrystall-ization temperature,fining grain size, expanding crystal lattice,increasingdislocation density and decreasing stacking fault ertergy,forming stable RE oxidation by internal oxidation,and so on,were observed.They were strengt- hening ensitive factors.The influence of the factors on strength properties and elongation of Pd was discussed.