Papers by Keyword: Mg-Nd-Zn-Zr

Abstract: This paper reports a significant increase in tensile ductility in solution-treated Mg-Nd-Zr cast alloy by trace addition of 0.2wt.% Zn. The improvement is accompanied by the occurrence of wavy slip lines on the surface of fractured tensile specimens, which are caused by the activation of non-basal slips including <a> and <a+c> or <c> non-basal dislocations, while these non-basal slips are hardly observed in Mg-Nd-Zr alloy without Zn addition.

Abstract: This paper reports results on the precipitation of metastable phases b'' and b' in Mg-3.1Nd-0.25Zn-0.45Zr wt.% during isothermal aging. H-shaped particles composed of Zn₂Zr₃ rods and plate-shape b' precipitates were observed in the peak aged samples. The Zn₂Zr3 particles serve as additional nucleation sites for the Mg-Nd precipitates and influence the kinetics of the precipitation sequence.

Abstract: Nano-indentation technique was used to survey creep stress exponent of ZM6 (Mg-2.8Nd-0.7Zn-0.6Zr) alloy at room temperature. The results showed that average press creep stress exponent of ZM6 alloy was about 89.75, and independent of strain rate and hardness, which has been verified by linear relationship of the double logarithmic plots between strain rate ( ε& ) and hardness (H ) measured by a nano-indentation equipment with constant load of 500mN.

Abstract: The microstructure of Mg-3wt%Nd-0.2wt%Zn-0.4wt%Zr (NZ30K) alloy after solution treatment was investigated and several kinds of interesting phases containing zirconium were found in this study. NZ30K was gravity cast using permanent die casting. After high tempering solution treatment at 540°C, cluster particles were observed inside the grains under optical microscopy. The detailed investigations were carried out on transmission electron microscopy (TEM). Four kinds of precipitates were visible inside grains with different shapes: block-like, globular, short rod-like, long rod-like. The block-like particle was identified as ZrH2 phase and the globular one was Zn2Zr3 phase. The other two were still Zr-containing phases, which could not be identified to any of existed compounds containing Zr. The formation of Zn-Zr compounds would probably be due to relative high ratio of Zr to Zn in the center of grains. ZrH2 would be the results of reaction of zirconium with H element during solution treatment, which probably came into the alloy during melting.