Preparation of a metastable high temperature phase (. gamma. -Dy sub 2 S sub 3 ) and a metastable high pressure phase (. gamma. -Y sub 2 S sub 3 ) by mechanical alloying and mechanical milling

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Scripta Metallurgica; (United States)

OSTI ID:5171072

Han, S H; Gschneidner, Jr, K A; Beaudry, B J ^[1]

---

1. Ames Lab., IA (United States)

Mechanical Alloying (MA) is a dry, high energy ball milling process which was developed by scientists and engineers to prepare alloys in which the two components have widely different melting points and are difficult if not impossible to prepare by other techniques. Mechanical Milling (MM) is a similar process, except a single phase material is subjected to the high energy ball milling, usually to produce fine crystalline or amorphous powders. MA has been mainly applied to produce commercial oxide dispersion-strengthened (ODS) alloys and in the last several years the research emphasis has focused on amorphization induced by MA. It is believed that the balance between cold welding and fracturing causes the crystalline phase to be transformed into an amorphous phase after long term MA. As far as we are aware, only a little has been reported on the use of MA or MM to prepare metastable crystalline phases. In this paper the authors present some initial results on the use of MA and MM to prepare a metastable high temperature phase {gamma}-Dy{sub 2}S{sub 3} and a metastable high pressure phase {gamma}-Y{sub 2}S{sub 3} at room temperature. This work was prompted by the need to prepare the low temperature polymorph of (R{sub 2{minus}x}Cu{sub x})S{sub 3}, where R = Dy or Y, as possible thermoelectric materials, and it was felt that MA of Cu and R{sub 2}S{sub 3} offered the best way to prepare these single phase solid solution alloys.

• DOE Contract Number: W-7405-ENG-82
• OSTI ID: 5171072
• Journal Information: Scripta Metallurgica; (United States), Vol. 25:1; ISSN 0036-9748
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
30 DIRECT ENERGY CONVERSION
DYSPROSIUM SULFIDES
CHEMICAL PREPARATION
THERMOELECTRIC MATERIALS
PHASE TRANSFORMATIONS
YTTRIUM SULFIDES
HIGH PRESSURE
HIGH TEMPERATURE
METASTABLE STATES
MILLING
SOLID SOLUTIONS
THERMOMECHANICAL TREATMENTS
CHALCOGENIDES
DISPERSIONS
DYSPROSIUM COMPOUNDS
ENERGY LEVELS
EXCITED STATES
FABRICATION
HEAT TREATMENTS
MACHINING
MATERIALS
MATERIALS WORKING
MIXTURES
RARE EARTH COMPOUNDS
SOLUTIONS
SULFIDES
SULFUR COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
360601* - Other Materials- Preparation & Manufacture
360602 - Other Materials- Structure & Phase Studies
300303 - Thermoelectric Generators- Materials
Components
& Auxiliaries