creator Yin, Ming advisor Nash, Philip Heusler compounds are ternary intermetallics with many promising properties such as spin polarization and magnetic shape memory effect. A better understanding of their thermodynamic properties facilitates future design and development. Therefore, standard enthalpies of formation and heat capacities from room temperature to 1500 K of selected Heusler compounds X2YZ (X = Co, Fe, Ni, Pd, Rh, Ru; Y = Co, Cu, Fe, Hf, Mn, Ni, Ti, V, Zr; Z = Al, Ga, In, Si, Ge, Sn) and half-Heusler compounds XYSn (X = Au, Co, Fe, Ir, Ni, Pd, Pt, Rh; Y = Hf, Mn, Ti, Zr) were measured using high temperature direct reaction calorimetry. The measured standard enthalpies of formation were compared with those predicted from ab initio calculations and the extended semiempirical Miedema's model. Trends in standard enthalpy of formation with respect to the periodic classification of elements were discussed. The effect of a fourth element (Co, Cu, Fe, Pd; Ti, V; Al, Ga, In, Si, Ge) on the standard enthalpy of formation of Ni2MnSn was also investigated. Lattice parameters of the compounds with an L21 structure were determined using X-ray powder diffraction analysis. Differential scanning calorimetry was used to determine melting points and phase transformation temperatures. Phase relationships were investigated using scanning electron microscopy with an energy dispersive spectrometer. The isothermal section of the Fe-Sn-Ti ternary system at 873 K was established using equilibrated alloys. Three ternary compounds including the Heusler compound Fe2SnTi were observed. A new ternary compound Fe5Sn9Ti6 was reported and the crystal structure of FeSnTi2 was determined for the first time. Submitted by Erma Thomas (thomase@iit.edu) on 2016-03-31T18:52:39Z No. of bitstreams: 1 etdadmin_upload_395052.zip: 17749737 bytes, checksum: b61ad4f63d942c92fb4437e5df908910 (MD5) Made available in DSpace on 2016-03-31T18:52:42Z (GMT). No. of bitstreams: 1 etdadmin_upload_395052.zip: 17749737 bytes, checksum: b61ad4f63d942c92fb4437e5df908910 (MD5) Previous issue date: 2015-12 Ph.D. in Mechanical, Materials and Aerospace Engineering 2015 2015-12 http://hdl.handle.net/10560/3778 en Calorimetry Enthalpy of Formation Heat Capacity Heusler Compound Phase Diagram Thermodynamics Dissertation born digital application/pdf In Copyright http://rightsstatements.org/page/InC/1.0/ Restricted Access MMAE / Mechanical, Materials, and Aerospace Engineering Illinois Institute of Technology Affiliated department