Aluminum Alloys, Processing and Characterization: Solidification and Casting
Sponsored by: TMS Light Metals Division, TMS: Aluminum Committee
Program Organizers: Yanjun Li, Norwegian University of Science and Technology
Wednesday 8:30 AM
March 1, 2017
Location: San Diego Convention Ctr
Session Chair: Shouxun Ji, Brunel niversity
8:30 AM Introductory Comments
A Model for α-Al(Mn,Fe)Si Crystals: Christian Simensen1; Are Bjørneklett1; 1SINTEF
A series of large crystals of α-Al(Mn,Fe)Si has been analyzed using microprobe, X-ray diffraction, pychnometer and electrical devices The cubic phase α-Al(Mn,Fe)Si has a density varying from 3520 kg/m3 to 3620 kg/m3. When iron is increased from 1.9 wt% to 20.8 wt%, the content of silicon is reduced from 10.7 wt% to 8.6 wt%. The phase had a low electrical resistivity, 2x10-6 Ωm. Large crystals of α-AlMnSi had a large Seebeck coefficient viz. 42 µV/⁰C. All the crystals were n-semiconductors. A new model for α-AlMnSi has been proposed where Si-atoms are connected in hexagonal rings around 0,0,0 and ½,½,½. The rings are linked by Mn and Si atoms, all covalent bonded. According to this model the ideal α-AlMnSi crystals have 24 Mn-, 18 Si- and 96 Al-atoms in the unit cell. Fe+Al can substitute for Mn + Si atoms in the unit cell. Vacancies can form on Mn-sites.
Casting Characteristics of High Cerium Content Aluminum Alloys: David Weiss1; Orlando Rios2; Zachary Sims2; Scott McCall3; Ryan Ott4; 1Eck Industries, Inc.; 2Oak Ridge National Laboratory; 3Lawrence Livermore National Laboratory; 4The Ames Laboratory
This paper compares the castability of near eutectic aluminum-cerium alloy system to the aluminum-silicon and aluminum-copper systems. The alloys are compared based on die filling capability, feeding characteristics, tolerance to casting defects and tendency to hot tear in both sand cast and permanent mold applications. Differential Scanning Calorimetry (DSC) analysis of the alloys systems is discussed. The castability ranking of the binary systems is as good or better than the aluminum-silicon system with some deterioration as additional alloying elements are added. In alloy systems that use cerium in combination with common aluminum alloying elements such as silicon, magnesium and/or copper, the casting characteristics are generally better than the aluminum-copper system. In general, production systems for melting, de-gassing and other processing of aluminum-silicon or aluminum-copper alloys can be used without modification for conventional casting of aluminum-cerium alloys.