SMAT2008M11NEW TECHNOLOGY FOR COMPOSITES BASEDON TUNGSTEN POWDER OBTAININGCristina Ileana 1 PASCU 1, Alexandru 2 STANIMIR 2Abstract. This paper presents a study on the quality of composites, based on tungsten pow<strong>de</strong>r, realized by a newproposed technology, which eliminates the operation of the paraffin infiltration and, also, the uniaxial die compactionthat is the dominant mo<strong>de</strong> of pow<strong>de</strong>r compaction. But the pow<strong>de</strong>r does not respond uni<strong>for</strong>mly to the applied pressure,consequently obtaining the target <strong>de</strong>nsity and the strength levels are the primary concerns. Because tungsten is apow<strong>de</strong>ry metal with a high melting temperature, the technical itinerary of sintering with liquid phase, typical <strong>for</strong>Pow<strong>de</strong>r Metallurgy, is the only mechanism that produces heavy alloys with a high <strong>de</strong>nsity. Also, <strong>for</strong> eliminate theoperation of the paraffin infiltration, it was tested with copper 2% as an additional element and then prepared throughisostatic pressing. N this studyt is un<strong>de</strong>rlined the influence of some technological parameters on the quality of thesepseudoalloys. Finally, a comparative study has been ma<strong>de</strong> between the final values of the hardness, <strong>de</strong>nsity and themicrostructural aspects, of these compositess based on W-pow<strong>de</strong>r, obtained through the new proposed technology andthe actual technology by Pow<strong>de</strong>r Metallurgy.Keywords: hydrostatic pressure, new technology, composite, tungsten, <strong>de</strong>nsity, hardnessPascu Ileana, PhD., Assoc. Professor, University of <strong>Craiova</strong>, Faculty of Mechanics, e-mail:i_pascu@yahoo.com, tel.: +40-251-543739.Stanimir Alexandru, Phd., Professor, University of <strong>Craiova</strong>, Faculty of Mechanics, e-mail:alexstanimir@yahoo.com, tel.: +40-251-543739.SMAT2008M12INFLUENCES OF WEAR OF PCBN INSERTS, DEPTH OF CUT, FEEDRATE AND CUTTING SPEED ON SURFACE ROUGHNESS IN FINISHTURNING OF HARDENED 205 CR115 STEELAlexandru STANIMIR, Ileana Cristina PASCUAbstract: In this study, the influences of cutting edge wear, <strong>de</strong>pth of cut, feed rate and cutting speed on surfaceroughness in finish turning of har<strong>de</strong>ned 205 Cr115 steel were experimentally investigated. In or<strong>de</strong>r to find out amathematical relation of polynomial type which has to <strong>de</strong>scribe how the roughness parameter Ra <strong>de</strong>pends by the 4consi<strong>de</strong>red influence factors, it has been used a composed, central with 25 experience program. This research resultsshows that <strong>for</strong> the domains of variation chosen <strong>for</strong> the consi<strong>de</strong>red parameters a p , f, V c and VB, the <strong>de</strong>pth of cut andcutting speed influence in a smaller measure the roughness of cutting edges. Instead, the roughness is rising once withthe advance and shows a variation with minimum function by wear , the smoothest surfaces being obtained <strong>for</strong> a wearVB = 0,05..0,15mm. The <strong>de</strong>termined relation shows that even the interactions of one of consi<strong>de</strong>red factors couldinfluence in a significant way he roughness of cutting edges.Keywords: har<strong>de</strong>ned steel, roughness, PCBN, wear, <strong>de</strong>pth of cut, feed rate, cutting speedAlexandru Stanimir, PhD., Assoc. Professor, University of <strong>Craiova</strong>, Faculty of Mechanics,Department of Materials and Technologies,e-mail:alexstanimir@yahoo.com tel.: +40-351-806684.Ileana Pascu, PhD., Assoc. Professor, University of <strong>Craiova</strong>, Faculty of Mechanics, e-mail:i_pascu@yahoo.com60
SMAT2008M13NITINOL: PROPERTIES AND APPLICATIONSDaniela TARNITA, Dan TARNITA, Nicu BIZDOACA, Cosmin BERCEANUAbstract: The paper presents the principal properties and ones of the most known applications of Nitinol. SMAbased on Ni-Ti alloy are the alloys most frequently used in commercial applications because they combine goodmechanical properties with shape memory effect. One of the most known intelligent materials is nitinol which offersmany functional advantages over conventional implantable alloys. Applications of SMA to the biomedical field havebeen successful because of their functional qualities, enhancing both the possibility and the execution of less invasivesurgeries. The biocompatibility of these alloys is one of their most important features. Different applications exploitremarkable properties of Nitinol like: superelasticity and <strong>for</strong>ce hysteresis, the shape memory effect (one-way or twoway),the steerability and torquability, less sensitivity to magnetic resonance imaging, excellent corrosion resistance.Because of their properties, there is a great technological interest in the use of SMA <strong>for</strong> different applications. SuperelasticNitinol has become a material of strategic importance as it allows to overcome a wi<strong>de</strong> range of technical and<strong>de</strong>sign issues relating to the miniaturization of different medical or nonmedical <strong>de</strong>vices.Keywords: Nitinol, properties, nonmedical applications, medical applicationsDaniela Tarnita, Prof.dr.eng., University of <strong>Craiova</strong>, Department of Applied Mechanics,dtarnita@yahoo.comDan Tarnita, Conf.dr., University of Medicine and Pharmacy, Department of Anatomy,dan_tarnita@yahoo.comNicu Bizdoaca, Prof.dr.eng., University of <strong>Craiova</strong>, Department of Mechatronics and Robotics,nicu@robotics.ucv.roPLASTIC DEFORMATION OF MATERIAL IN THE AREACUTTING PROCESSING THROUGH VIBROSPLINTERINGSMAT2008M14Bebe TICA Stefanita CIUNELAbstract. This paper <strong>de</strong>monstrates that the <strong>de</strong><strong>for</strong>mation of material in the area <strong>for</strong> the <strong>de</strong>ployment of chips byvibrosplintering fall into the simple pattern of <strong>de</strong><strong>for</strong>mation of the splinter, namely adiabatic shear.This pattern of distortion and low orează ef<strong>for</strong>t shearing unit, which leads to a reduced consumption of energy,so a atuu in addition to using ultrasonic vibrosplintering method of processing superfine, <strong>de</strong>monstrated in other worksby authors.Keywords: cutting process, vibrosplintering, splinter, mouldabilityBebe TICA - Ph.D. Associate Professor, Road Vehicle Department, Faculty of Mechanics,ticabebe@yahoo.comStefanita CIUNEL - Assistant Professor, Road Vehicle Department, Faculty of Mechanics,ciunelstefanita@yahoo.com61