The effects of field-evaporation rate on the quantitative chemical analysis of materials by atom-probe field-ion microscopy are considered. Examples of erroneously high measured values of the Ti concentration in Mo-1.0 at.% Ti and Mo-1.0 at.% Ti-0.08 at.% Zr (TZM) alloys are presented and the cause is shown to have been due to a high field-evaporation rate. The basic arguments used to explain t...

The chemical disorder intrinsic to high entropy alloys inevitably creates diffuse scattering in their x-ray or neutron diffraction patterns. Through first principles hybrid Monte Carlo/molecular dynamics simulations of two BCC high entropy alloy forming compounds, CrMoNbV and NbTiVZr, we identify the contributions of chemical disorder, atomic size and thermal fluctuations to the diffuse scatter...

Ab initio generalized valence bond, configuration interaction, and multiconfiguration self-consistent field calculations have been performed to examine the properties of the early-late transition metal bimetallic cluster ZrPt,, as a representative model of Engel-Brewer compounds. Such intermetallic compounds are known to be extremely thermally stable in the bulk form. We find the atomization en...

Results of calorimetric, differential thermal analysis, and structural measurements are presented for a series of bulk metallic glass forming compositions in the Zr–Ti–Cu–Ni–Be alloy system. The calorimetric data for five alloys, prepared along the tie line between phase separating and nonphase separating compositions, show that the transition from phase separating to nonphase separating behavi...

In the present chapter, results of our recent investigations on the role of gallium (Ga) on the aluminum (Al) site in Zr69.5Al7.5-xGaxCu12Ni11 metallic glass (MG) composition have been discussed. The material tailoring and cooling rate effects on the mechanical behavior of Zr-based metallic glasses and their nanocomposites have been studied. The substitution of Ga on the Al site in Zr–Al–Cu–Ni ...

Introduction: During our nano-mineralogy investigation of the Allende meteorite, we discovered two new minerals that occur as microto nano-crystals in refractory inclusions: Allendeite, Sc4Zr3O12, a new Scand Zr-rich oxide; and hexamolybdenum, (Mo,Ru,Fe), a Mo-dominant alloy. Allendeite, which may be an important ultra-refractory carrier linking Zr-, Scoxides and the more common Sc-, Zr-enriche...

Nanoindentation with spherical and Berkovich indenters, reciprocating wear and dynamic impact tests were conducted to investigate the deformation and wear behavior of two Zr-based metallic glasses. The results indicated that the indenter shape may have an effect on the displacement bursts in the load-penetration curves as no apparent bursts could be observed when a Berkovich indenter was used. ...

An investigation into the weldability of the Al-Li-Cu-Mg-Zr alloy 8090 using a CO, laser indicates that the grain structure and microstructure of the weld zone are sensitive to the post-weld heat treatment. If a slow heating rate of 1Krnin-I to the solution treatment temperature is used the formation of P' (AIJr) dispersoids is promoted which leads to a uniformly small grain size within the fus...