title: [The design of Co-Cr-Mo alloy combining the framework with porcelain fused to metal restorations and determination of the mechanical properties].
abstract: OBJECTIVE
  To investigate a kind of Co-Cr-Mo alloys used for both porcelain fused to metal (PFM) restorations and casting framework of removable partial dentures.
  
  
  METHODS
  The Co-Cr-Mo alloy underwent the design for elementary compositions of the alloys and the production from the raw materials by means of a vacuum melt furnace. The strength, hardness, plasticity and casting ability of the alloy were examined with metal tensile test. Vickers hardness test and grid casting were examined respectively. The microstructure of the Co-Cr-Mo alloy was also inspected by scanning electron microscope and X-ray diffraction analysis.
  
  
  RESULTS
  The elementary composition of DA9-4 alloy mainly consisted of Co 54%-67%, Cr 21%-26%, Mo 5%-8%, W 5%-8%, Si 1%-3%, Mn 0.1%-0.25% and trace elements. The yield strength of the alloy was 584 MPa, while the tensile strength was 736 MPa. The coefficient of expansion was 15.0%, the Vickers hardness reached 322, and the casting ratio exibited 100%.
  
  
  CONCLUSIONS
  The DA9-4 Co-Cr-Mo alloy used for PFM and framework shown in this paper can meet the clinical demands and have reached the objects of the experiment plan.
authors.affiliation: Dept. of Prosthodontics, West China College of Stomatology, Sichuan University, Chengdu, China.
authors.forename: Yong-lie
authors.initials: YL
authors.lastname: Chao
authors.forename: Chang-hong
authors.initials: CH
authors.lastname: Lui
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Xiao-yu
authors.initials: XY
authors.lastname: Yang
mesh_terms: D000497:Alloys; D002858:Chromium Alloys; D003776:Dental Porcelain; D006244:Hardness; D008422:Materials Testing; D016876:Metal Ceramic Alloys; D008670:Metals; D013499:Surface Properties
chemical_list: D000497:Alloys; D002858:Chromium Alloys; D016876:Metal Ceramic Alloys; D008670:Metals; D003776:Dental Porcelain