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Materials assurance through orthogonal materials measurements: X-ray fluorescence aspects

Powder Diffraction

Rodriguez, Mark A.; Van Benthem, Mark V.; Susan, D.F.; Griego, James J.M.; Yang, Pin Y.; Mowry, Curtis D.; Enos, David E.

X-ray fluorescence (XRF) has been employed as one of several orthogonal means of screening materials to prevent counterfeit and adulterated products from entering the product stream. We document the use of principal component analysis (PCA) of XRF data on compositionally similar and dissimilar stainless steels for the purpose of testing the feasibility of employing XRF spectra to parse and bin these alloys as the same or significantly different alloy materials. The results indicate that XRF spectra can separate and assign alloys via PCA, but that important corrections for detector drift and scaling must be performed in order to achieve valid results.

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TYPE Conference Poster YEAR 2017
ScopusOSTIDOI

Mechanical and Functional Behavior of High-Temperature Ni-Ti-Pt Shape Memory Alloys

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

Buchheit, Thomas E.; Susan, D.F.; Massad, Jordan M.; McElhanon, James R.; Noebe, Ronald D.

A series of Ti-rich Ni-Ti-Pt ternary alloys with 13 to 18 at. pct Pt were processed by vacuum arc melting and characterized for their transformation behavior to identify shape memory alloys (SMA) that undergo transformation between 448 K and 498 K (175 °C and 225 °C) and achieve recoverable strain exceeding 2 pct. From this broader set of compositions, three alloys containing 15.5 to 16.5 at. pct Pt exhibited transformation temperatures in the vicinity of 473 K (200 °C), thus were targeted for more detailed characterization. Preliminary microstructural evaluation of these three compositions revealed a martensitic microstructure with small amounts of Ti2(Ni,Pt) particles. Room temperature mechanical testing gave a response characteristic of martensitic de-twinning followed by a typical work-hardening behavior to failure. Elevated mechanical testing, performed while the materials were in the austenitic state, revealed yield stresses of approximately 500 MPa and 3.5 pct elongation to failure. Thermal strain recovery characteristics were more carefully investigated with unbiased incremental strain-temperature tests across the 1 to 5 pct strain range, as well as cyclic strain-temperature tests at 3 pct strain. The unbiased shape recovery results indicated a complicated strain recovery path, dependent on prestrain level, but overall acceptable SMA behavior within the targeted temperature and recoverable strain range.

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TYPE Journal Article YEAR 2016
ScopusOSTI
Results 51–75 of 134
Results 51–75 of 134