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Abstract:The effect of Ni-content on phase transformation behavior of NiTi-20 at. % Zr high temperature shape memory alloy (HTSMA) is investigated over a small composition range, i.e., 49.8, 50.0 and 50.2 at. % Ni, by differential scanning calorimetry (DSC), high-energy synchrotron radiation X-ray diffraction (SR-XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). All samples show a monoclinic B19 martensitic structure at room temperature. It is shown that even with these small variations in Ni-content, the alloy shows vastly different transformation temperatures and responds in a drastically different manner to aging treatments at 550 and 600 • C. Lastly, a discussion on H-phase composition with respect to bulk composition is presented.

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In a preliminary study of American silver plated cultural heritage objects with the Dallas Museum of Art (DMA), variable plating thickness was observed, which complicates non-destructive characterization of the base metal. Therefore, it is the objective of this study is to compare the effectiveness of three nondestructive complementary analytical methods to characterize both the plating and base metal of a typical silver Ag-plated object and to contrast these results with conventional destructive metallographic methods. An externally purchased sacrificial "Century" fork was chosen for this study and is similar to one found in the DMA's collection. First conventional destructive metallographic methods, where crosssections were taken and then characterized using optical microscopy (OM) and scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS), were employed in order to evaluate the effectiveness of the non-destructive methods. The first non-destructive method, synchrotron radiation X-Ray diffraction (SR-XRD), reveals the plating thickness, texture related to processing methods, and the phases present in both the base metal and plating. The second method , dual beam focused ion beam (FIB) / (SEM) equipped with an (EDS) system, provides elemental composition of both the plating and base metal, as well as imaging of the plating thickness and grain structure, giving some insight into processing methods. The last non-destructive method, handheld X-Ray Fluorescence (XRF) spectroscopy, provides qualitative elemental compositions of both the plating and base metals. Each non-destructive analytical method yields complementary results about the composition, plating thickness, texture, and phases present in the plating and base metals of the Ag-plated "Century" fork and aids in the verification of the results from the other methods. Through these methods, we show that successful characterization of Agplated cultural heritage objects is possible non-destructively, thus maintaining the object's structural, historical and artistic integrity.

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