Theoretical and Experimental Investigation on the Low Temperature Properties of the NbCr2 Laves Phase

stract This is is the final report rt of a three-year, -year, Laboratory ratory Directed ted Research arch and Development lopment (LDRD)) project j ct at Loss Alamos National tional Laboratory ratory (LANL). L). The goall of the project ject was to develop lop methodologies t odologies in which ich to define and rn s improve rove the properties erties of NbCrz so thatt the high temperature erature structural tural rz applications li ations of alloys based ed upon this would ld nott be limited it d by the lowbnhtle We accomplished plished this task temperature erature rit behavior avior of the intermetallic. ta lic. by (1) understanding erstanding the defectt structure ture and deformation r ation mechanisms hanisms in Laves es phases, ses, (2) electronic t nic and geometric etric contributions tributions to phase se stability ility and alloying ing behavior, avior, and (3) novell processing ce sing of duall phase se (Laves/bcc) structures. ctures. As a result lt alloys with properties erties thatt in many casess surpass a s superalloys ra loys were re developed. l ped. Forr example, le, we have tailored red alloy design i n strategies t gies and processing ce sing routes tes in a metall alloy to achievee ambient ient temperature erature ultimate ate strengths gths of 2.35 GPa as welll as ultimate te strengths ngths of 1000”C. This is results lts in one of the strongest gest metall alloyss that es/bee) 1.5 GPaa at 0°e. currently rently exist, t, while ile stilll having i g deformability r ability at room temperature. erature. Background ckground andd Research search Objectives jectives Applications plications off Intermetallic termetallic Phases ases In the past st thirty t years, s, intermetallic eta lic phases ses have experienced rienced growing ing markets ets in material ri l applications li ations due to theirr unique i ue properties. erties. Forr example, le, the hardness ne s and strength, th, special ial magnetic etic properties, erties, chemical ical resistance, i tance, and semiconducting iconducting properties erties are just st a few properties erties in which i h intermetallics eta lics have foundd applications. lications. However, ever, the most st abundant dant classs of intermetallics, eta lics, the Laves phases es (overr 360 defined i ed binary ry phases), ses), are the leastt utilized of the intermetallics. eta lics. Historically, t rica ly, Lavess phases ses havee been perceived ived as a "pest" to the steell and superalloy ra loy industries stries due to grain boundary ndary embrittlement ri tlement “ t” problems le s associated ciated with the complex lex structured tured Lavess phase se precipitates. ipitates. Forr this reason,, Lavess phases ses were re typically ly avoided, i ed, until il it was discovered vered thatt Lavess phase se precipitates, i itates, thoma@lanl. gov *Principal i cipal Investigator, stigator, e-mail: il: a lanl.