稀土在石油套管钢中的应用研究

稀土在Ｊ－５５钢级套管钢中有净化钢液，变质夹杂和微合金化作用，提高了钢的横向冲击值和抗裂纹扩展能力，显著改善了抗射孔开裂性能。稀土变质ＭｎＳ和Ａｌ２Ｏ３夹杂的程度，分别取决于钢中稀土与锰和稀土与铝的活度比值，而活度比值决定了钢中ＲＥＡｌＯ３和ＲＥ２Ｏ２Ｓ的相对数量和性能。     

Enhanced plasticity of a Zr50Cu48Al2 bulk metallic glass

In this work, a Zr₅₀Cu₄₈Al₂ bulk metallic glass (BMG) with improved glass forming ability and mechanical properties was synthesized by adding a small amount of Al to a Zr-Cu binary glass-forming alloy. The as-cast Zr₅₀Cu₄₈Al₂ glassy rod does not exhibit macroscopic failure under compression at room temperature indicating the excellent plasticity of the BMG. The deformation behavior of the BMG was studied intensively by examining the true stress-strain curve and the surface morphology of the post-deformation sample. The effect of minor Al addition on the mechanical properties including the fracture stress, the modulus, and the kinetic characteristics of the BMG was also investigated. The enhanced plasticity of the BMG is considered to be related to its reduced fragility parameter m value.