While phase structure and texture have been measureable quantities since the early 1900s, we still have very little idea how accurate or precise these measurements are.

Manufacturers are currently designing and creating alloys that have multiple phases present. Examples such as advanced high strength steels (AHSS) like as dual phase (DP), transformation induced plasticity (TRIP), quenched & partitioned (Q&P), and complex phase (CP) steels, as well as precipitation hardened aluminum alloys require accurate measurements of the amount of each phase in the material, as well as how the phase fractions evolve during processing and deformation.

Similarly, the grain orientations in most engineering materials have some preferential distribution due to processing conditions and deformation history, referred to as crystallographic texture. This texture affects the initial material properties and evolves as a function of deformation. Accurate measurement of the crystallographic texture is the key to understanding how the material will respond during forming of parts for automotive, aerospace, or other industrial applications.

While there are a number of techniques used to measure phase fraction or crystallographic texture, the accuracy and precision is not well quantified, leading to significant differences between methods. NIST has world-class facilities in neutron, magnetic, X-ray, and electron techniques to investigate these methods; compare between different methods; and provide improved techniques and/or methods. We work heavily with industrial and academic partners to improve these measurements.

 

key words

Crystallographic texture; Phase fraction; Electron backscatter diffraction (EBSD); Neutron diffraction; X-ray diffraction (XRD); Steel; Automotive lightweighting; Retained austenite; Automotive manufacturing;

Citizenship:  Open to U.S. citizens

Level:  Open to Postdoctoral applicants