Properties of Lanthanum Containing Free-machining Titanium Alloys with Re-gard to Localized Corrosion
Titanium alloys combine outstanding specific mechanical properties with corrosion resistance and biocompatibility. Addition of lanthanum to (a +β)titanium alloys like Ti6Al4V leads to improved machinability due to formation of short breaking chips and thus,the possibility of automated manufacturing. These alloys consist of a titanium matrix and metallic lanthanum particles located on the grain boundaries. Free-machining alloys based on Ti6Al4V have been developed by replacing vanadium with an iron-molybdenum pre-alloy to lower the material costs, by adding lanthanum to improve machinability and copper and silicon to improve particle distribution. Two alloys, Ti6Al2FelMo0. 9La0. 5Cu and Ti6Al2FelMo0. 9La0. 5Cu0. 3Si,have been investigated. Both alloys contain precipitates of lanthanum as well as Cu4 La intermetallic phase besides the (α-β)-matrix. The focus of this work lies on the characterisation of the local corrosion properties by atomic force microscopic methods, like Scanning Kelvin Probe Force Microscopy (SKPFM) and in-situ Atomic Force Microscopy (EC-AFM) in a fluid cell to understand the underlying corrosion mechanisms. Integral testing methods like potentiodynamic polarization and electrical impedance spectroscopy (EIS) are also conducted. The alloys have been exposed to different corrosive media. The results show that the precipitates; undergo selective dissolution in time intervals of a few minutes up to several hours depending on the electrolyte.
Titanium corrosion afm lanthanum microstructure
Francesco Depentori Judith Laukart Sigrid Benfer Carsten Siemers Wolfram Fiirbeth
DECHEMA e. V.,Karl-Winnacker-Institut,Theodor-Heuss-Allee 25,D-60486 Frankfurt am Main,Germany Technische Universitat Braunschweig,Institut furWerkstoffe,Langer Kamp 8,D-53655 Braunschweig,German
国际会议
The 12th World Conference Titanium(第十二届世界钛会 Ti-2011)
北京
英文
1915-1919
2011-06-19（万方平台首次上网日期，不代表论文的发表时间）