ISSN:
1662-9752
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Maschinenbau
Notizen:
Extrusion is a way to produce near net shape components from CP grade titaniumpowders of optimum density with minimum porosity and acceptable mechanical properties.Chemically pure, hydride/dehydride titanium powders were cold pre-compacted and extruded at850oC under an argon atmosphere. The extrusion stress required was ~450MPa. To characterizethe extrusions, the porosity distribution, qualitative microstructure and tensile properties wereevaluated and compared with conventional extruded wrought titanium. Extrusion occurred afterthe green billets were upset to ~100% of theoretical density and adequate lubrication was applied tothe die. The resultant product was 100% dense with a narrow band of surface porosity andexhibited an equiaxed microstructure of similar magnitude to the starting material. The tensileproperties of the bars were observed to be significantly superior to conventionally extruded CPtitanium bar products, a result associated with the much finer average grain size. Outcomes fromthis study have assisted in the identification of a number of key characteristics important to theextrusion of titanium from pre-compacted CP titanium powders, allowing the elimination ofcanning and hot isostatic pressing (HIPping) of billets prior to extrusion as per conventional PMprocesses
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/14/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.534-536.801.pdf
