{"id":{"repo_id":"nus","oai_identifier":"oai:scholarbank.nus.edu.sg:10635/161072"},"canonical_url":"https://search.dev.ndltd.org/etd/nus/oai:scholarbank.nus.edu.sg:10635/161072","repository":{"repo_id":"nus","name":"National University of Singapore","base_url":"https://scholarbank.nus.edu.sg/oai/request"},"display":{"title":"Abnormal Grain Growth of Tungsten Carbide in Small Amount of Cobalt: Mechanism and Application","abstract":"<P>CONSIDERABLE ABNORMAL GRAINS WERE OBSERVED IN LIQUID PHASE SINTERED CEMENTED WC WITH 0.2~0.9WT% COBALT. MICROSTRUCTURE EXAMINATIONS SHOWED GRAIN BOUNDARIES PARALLEL TO (0001) PLANES AND AGG WAS EXPLAINED BY GRAIN BOUNDARY RE-ENTRANT EDGE (GBRE) ASSISTED 2-D NUCLEATION PROCESS. GRAIN COALESCENCE IN LIQUID COBALT WAS ASSUMED TO BE THE SOURCE FOR THE GRAIN BOUNDARIES.</P><P>THE DENSITY OF ABNORMAL GRAINS COULD BE TAILORED BY THE COMPOSITIONS AND SINTERING CONDITIONS AND THE FRACTURE TOUGHNESS COULD BE IMPROVED BY INTRODUCING ABNORMAL GRAINS, BUT AT SOME EXPENSE OF HARDNESS. THE HIGHEST VALUE OF FRACTURE TOUGHNESS, 7.34 MPAB \"M0.5, WAS ACHIEVED FOR WC-0.5WT%CO-0.25WT%VC. </P><P>TWO-MATERIAL POWDER INJECTION MOLDING WAS APPLIED TO SYNTHESIZE DOUBLE LAYERED COMPONENTS WITH GRADED STRUCTURE. A HIGHER DENSITY OF ABNORMAL GRAINS BUT WITH SMALLER ASPECT RATIO WERE FOUND IN PIM SAMPLES. A GRADED STRUCTURE IN TERMS OF DENSITY OF ABNORMAL GRAINS WAS FORMED, ACCOUNTING FOR THE GRADED HARDNESS, BE","abstract_html":"&lt;P&gt;CONSIDERABLE ABNORMAL GRAINS WERE OBSERVED IN LIQUID PHASE SINTERED CEMENTED WC WITH 0.2~0.9WT% COBALT. MICROSTRUCTURE EXAMINATIONS SHOWED GRAIN BOUNDARIES PARALLEL TO (0001) PLANES AND AGG WAS EXPLAINED BY GRAIN BOUNDARY RE-ENTRANT EDGE (GBRE) ASSISTED 2-D NUCLEATION PROCESS. GRAIN COALESCENCE IN LIQUID COBALT WAS ASSUMED TO BE THE SOURCE FOR THE GRAIN BOUNDARIES.&lt;/P&gt;&lt;P&gt;THE DENSITY OF ABNORMAL GRAINS COULD BE TAILORED BY THE COMPOSITIONS AND SINTERING CONDITIONS AND THE FRACTURE TOUGHNESS COULD BE IMPROVED BY INTRODUCING ABNORMAL GRAINS, BUT AT SOME EXPENSE OF HARDNESS. THE HIGHEST VALUE OF FRACTURE TOUGHNESS, 7.34 MPAB &quot;M0.5, WAS ACHIEVED FOR WC-0.5WT%CO-0.25WT%VC. &lt;/P&gt;&lt;P&gt;TWO-MATERIAL POWDER INJECTION MOLDING WAS APPLIED TO SYNTHESIZE DOUBLE LAYERED COMPONENTS WITH GRADED STRUCTURE. A HIGHER DENSITY OF ABNORMAL GRAINS BUT WITH SMALLER ASPECT RATIO WERE FOUND IN PIM SAMPLES. A GRADED STRUCTURE IN TERMS OF DENSITY OF ABNORMAL GRAINS WAS FORMED, ACCOUNTING FOR THE GRADED HARDNESS, BE","abstract_has_math":false,"creators":["LI TAO"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2008,"date_issued":"2008-10-27","date_published":"2008-10-27","updated_at":"2026-07-24T03:32:43Z","subjects":["abnormal grain growth; cemented tungsten carbide; GBRE assisted 2-D nucleation; fracture toughness; powder injection molding"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["LI TAO"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2008-10-27"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://scholarbank.nus.edu.sg/handle/10635/161072"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["abnormal grain growth; cemented tungsten carbide; GBRE assisted 2-D nucleation; fracture toughness; powder injection molding"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://scholarbank.nus.edu.sg/bitstreams/dfe63fff-c8e2-4f4a-8f11-53671cab86cc/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["<P>CONSIDERABLE ABNORMAL GRAINS WERE OBSERVED IN LIQUID PHASE SINTERED CEMENTED WC WITH 0.2~0.9WT% COBALT. MICROSTRUCTURE EXAMINATIONS SHOWED GRAIN BOUNDARIES PARALLEL TO (0001) PLANES AND AGG WAS EXPLAINED BY GRAIN BOUNDARY RE-ENTRANT EDGE (GBRE) ASSISTED 2-D NUCLEATION PROCESS. GRAIN COALESCENCE IN LIQUID COBALT WAS ASSUMED TO BE THE SOURCE FOR THE GRAIN BOUNDARIES.</P><P>THE DENSITY OF ABNORMAL GRAINS COULD BE TAILORED BY THE COMPOSITIONS AND SINTERING CONDITIONS AND THE FRACTURE TOUGHNESS COULD BE IMPROVED BY INTRODUCING ABNORMAL GRAINS, BUT AT SOME EXPENSE OF HARDNESS. THE HIGHEST VALUE OF FRACTURE TOUGHNESS, 7.34 MPAB \"M0.5, WAS ACHIEVED FOR WC-0.5WT%CO-0.25WT%VC. </P><P>TWO-MATERIAL POWDER INJECTION MOLDING WAS APPLIED TO SYNTHESIZE DOUBLE LAYERED COMPONENTS WITH GRADED STRUCTURE. A HIGHER DENSITY OF ABNORMAL GRAINS BUT WITH SMALLER ASPECT RATIO WERE FOUND IN PIM SAMPLES. A GRADED STRUCTURE IN TERMS OF DENSITY OF ABNORMAL GRAINS WAS FORMED, ACCOUNTING FOR THE GRADED HARDNESS, BE"]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["d4a876f8b1eb8d33a664c5ae1aa8722f","e9bda2ade0631ee258811a5f9475fde7"]},{"key":"dc:title","label":"Title","values":["Abnormal Grain Growth of Tungsten Carbide in Small Amount of Cobalt: Mechanism and Application"]}]}],"canonical_facts":{"dc:creator":["LI TAO"],"dc:date.issued":["2008-10-27"],"dc:description.abstract":["<P>CONSIDERABLE ABNORMAL GRAINS WERE OBSERVED IN LIQUID PHASE SINTERED CEMENTED WC WITH 0.2~0.9WT% COBALT. MICROSTRUCTURE EXAMINATIONS SHOWED GRAIN BOUNDARIES PARALLEL TO (0001) PLANES AND AGG WAS EXPLAINED BY GRAIN BOUNDARY RE-ENTRANT EDGE (GBRE) ASSISTED 2-D NUCLEATION PROCESS. GRAIN COALESCENCE IN LIQUID COBALT WAS ASSUMED TO BE THE SOURCE FOR THE GRAIN BOUNDARIES.</P><P>THE DENSITY OF ABNORMAL GRAINS COULD BE TAILORED BY THE COMPOSITIONS AND SINTERING CONDITIONS AND THE FRACTURE TOUGHNESS COULD BE IMPROVED BY INTRODUCING ABNORMAL GRAINS, BUT AT SOME EXPENSE OF HARDNESS. THE HIGHEST VALUE OF FRACTURE TOUGHNESS, 7.34 MPAB \"M0.5, WAS ACHIEVED FOR WC-0.5WT%CO-0.25WT%VC. </P><P>TWO-MATERIAL POWDER INJECTION MOLDING WAS APPLIED TO SYNTHESIZE DOUBLE LAYERED COMPONENTS WITH GRADED STRUCTURE. A HIGHER DENSITY OF ABNORMAL GRAINS BUT WITH SMALLER ASPECT RATIO WERE FOUND IN PIM SAMPLES. A GRADED STRUCTURE IN TERMS OF DENSITY OF ABNORMAL GRAINS WAS FORMED, ACCOUNTING FOR THE GRADED HARDNESS, BE"],"dc:format.checksum.md5":["d4a876f8b1eb8d33a664c5ae1aa8722f","e9bda2ade0631ee258811a5f9475fde7"],"dc:identifier.uri":["https://scholarbank.nus.edu.sg/bitstreams/dfe63fff-c8e2-4f4a-8f11-53671cab86cc/download"],"dc:relation.isreferencedby":["https://scholarbank.nus.edu.sg/handle/10635/161072"],"dc:subject":["abnormal grain growth; cemented tungsten carbide; GBRE assisted 2-D nucleation; fracture toughness; powder injection molding"],"dc:title":["Abnormal Grain Growth of Tungsten Carbide in Small Amount of Cobalt: Mechanism and Application"],"dc:type":["Thesis"]},"updated_at":"2026-07-24T03:32:43Z"}