WO2007082708A1 - Semifinished part composed of an alpha/alpha2-titanium alloy and process for producing it - Google Patents
Semifinished part composed of an alpha/alpha2-titanium alloy and process for producing it Download PDFInfo
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- WO2007082708A1 WO2007082708A1 PCT/EP2007/000322 EP2007000322W WO2007082708A1 WO 2007082708 A1 WO2007082708 A1 WO 2007082708A1 EP 2007000322 W EP2007000322 W EP 2007000322W WO 2007082708 A1 WO2007082708 A1 WO 2007082708A1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
- C22F1/18—High-melting or refractory metals or alloys based thereon
- C22F1/183—High-melting or refractory metals or alloys based thereon of titanium or alloys based thereon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/20—Making machine elements valve parts
- B21K1/22—Making machine elements valve parts poppet valves, e.g. for internal-combustion engines
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C14/00—Alloys based on titanium
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K25/00—Details relating to contact between valve members and seat
- F16K25/005—Particular materials for seats or closure elements
Definitions
- the invention relates to a semifinished product based on ⁇ -titanium and intermetallic phases of the alloy system titanium-aluminum according to the preamble of claim 1 and a method for producing a component or a component component for an internal combustion engine according to the preamble of claim 5.
- a TiAl alloy is known from WO 2004/079237 A2, which is characterized by a high Al content and makes use of the curing by the ⁇ 2 phase.
- such an alloy has a high proportion of ⁇ -phase stabilizing elements, which have a negative effect on the high-temperature properties.
- the addition of ⁇ -phase stabilizing elements produces biphasic alloys ( ⁇ / ⁇ ) which have good strength at low and medium temperatures. As the cubic body-centered ß-phase (due to a higher diffusion coefficient) deforms more easily at higher temperatures than the ⁇ - and ⁇ . 2 phase, the high temperature strength of these alloys is limited.
- the invention has for its object to propose a material for components and components components in internal combustion engines based on the Ti-Al alloy system, which is characterized by low specific gravity, a particularly high rigidity and high strength at elevated temperatures. Furthermore, a method for the production of components and component components is to be provided from such a material.
- a semifinished product of an ⁇ -titanium alloy with a proportion of 40-50 vol .-% ⁇ 2 ⁇ phase (Ti 3 Al, ordered hexagonal phase) and 50-60 vol .-% ⁇ -phase is used to produce the components and component components .
- the semifinished product may additionally contain up to 1% by volume of suicides and in minor proportions (up to 1% by volume at operating temperature) of ⁇ -phase.
- the material of the semifinished product is preferably composed of 8-10% by weight of Al; 0.2-5.0% by weight Nb; 0.1-1.0 wt% Mo; 0.1-2.0% by weight of Si; 0.2-4.0 wt% Zr; 0.1-1.0 wt% B and the balance Ti together.
- Such an alloy has a low specific gravity and a fine-grained lamellar Microstructure.
- Particularly advantageous is a composition of 9 wt .-% Al; 0.5% by weight of Nb; 0.5% by weight of Mo; 0.5 wt% Si and the remaining wt% Ti exposed.
- Components made from the ⁇ -titanium alloys according to the invention have a yield strength> 1000 MPa at room temperature,> 550 MPa at 600 ° C. and> 250 MPA at 800 ° C. Its modulus of elasticity is> 125 GPa at room temperature. Since the alloys according to the invention have increased rigidity and high strength even at high temperatures, they are particularly suitable as material for components and component components in internal combustion engines which are exposed to high thermal and mechanical stresses during operation. Due to the high Al content and low content of heavy alloying elements, the alloys of the present invention have a low density (about 4.35 g / cm 3 ).
- the expression of ß-phase is suppressed, resulting in a high heat resistance.
- areas are formed in which there is an accumulation of ß-phase stabilizing elements, resulting in many strength-enhancing internal interfaces.
- the Si contained in the alloy of the invention results in effective solid solution strengthening and forms fine suicides; This results in an increase in strength over the entire temperature range.
- the ß-phase is therefore suppressed; the proportion of the ⁇ 2 phase is preferably> 30% by volume at 600 ° C. and preferably> 5% by volume at 800 ° C.
- the hot forming is preferably carried out at temperatures between 1000 ° C and 1150 ° C, in particular between 1050 ° C and 1110 ° C.
- the ⁇ -titanium alloy is used as a material for valves in internal combustion engines.
- the starting point for the production of such a valve is a cylindrical semi-finished product of an ⁇ -titanium alloy according to the invention, the diameter of which is smaller than the diameter of the valve to be manufactured.
- the semifinished product is hot-worked in the state region of the ⁇ -phase, preferably at 1050 ° C.-1110 ° C.
- the valve stem is formed by an extrusion process;
- the valve disk is formed by forging operation. In this way it is ensured that both the material in the valve stem and the material in the valve plate undergoes a minimum deformation and thereby the desired microstructural change.
- a single component (eg the valve stem) of the ⁇ -titanium alloy according to the invention can be hot-formed and connected in a subsequent step with another component (eg the valve disc) of the same or a different material be (eg by friction welding).
- the alloy according to the invention is suitable not only as a material for thermally highly stressed engine components and components, but also for low-temperature applications in which particularly high demands are made in terms of stiffness, strength and weight saving.
- the use of the alloy according to the invention as a valve material offers the possibility of higher engine speeds and thus higher powers.
- the production and processing of valves made of this alloy is analogous to the previously used, commercially available valves made of Ti alloys and is therefore much easier and less expensive than that of TiAl valves. Furthermore, there is a higher
- FIG. 3 is a representation of a chemical mapping of ribbon-like structures in the microstructure of FIG.
- Figure 1 shows the result of a modeling of the equilibrium phase proportions of the alloy Ti-9A1-O, 5Nb-0.5Mo-O, 5Si as a function of the temperature; this alloy composition (9% by weight Al, 0.5% by weight Nb, 0.5% by weight Mo, 0.5% by weight Si, remainder Ti) has proved to be particularly advantageous with regard to its heat resistance. Due to the low content of ß-stabilizers this alloy forms the ß-phase is not or in only minimal volume levels. Especially in the temperature range between 600 ° C and 800 ° C, the operating temperature of the considered here
- This multiphase microstructure is e.g. 2, which shows the microstructure of the alloy Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si and has band-like regions 1.
- This band-like regions 1 shows that these regions 1 are enrichments of ⁇ -stabilizers.
- diffraction patterns show that there is no beta phase in the band-like regions 1.
- the alloy according to the invention at high temperatures, the absence of the ⁇ -phase prevents the strength drop otherwise observed in ⁇ / ⁇ alloys. At the same time, the high proportion of 01 2 phase contributes to an increase in high-temperature strength. Another strength-increasing contribution is achieved by the addition of 0.5 wt .-% Si and the consequent mixed crystal structure and the excretion of fine Ti 5 Si 3 particles. Overall, the alloy Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si is superior to the conventional Ti alloys in terms of high-temperature strength and fatigue properties and is close to those of TiAl.
Abstract
An α/α2-TiAl alloy as material for components or parts of components in internal combustion engines, in particular for lightweight valves, comprises 40-50% by volume of α2 phase (Ti3Al), ≤ 1% by volume of silicides, ≤ 1% by volume of ß phase and the remainder α phase. This alloy has a high stiffness and strength. The components and parts of components are produced by hot shaping in the ß phase, preferably at 1050°C-1110°C, from a semifinished part composed of the abovementioned intermetallic phase which preferably has a chemical composition of 8-10% by weight of Al, 0.2-5.0% by weight of Nb, 0.1-1.0% by weight of Mo, 0.1-2.0% by weight of Si, 0.2-4.0% by weight of Zr, 0.1-1.0% by weight of B and Ti as balance.
Description
HALBZEUG AUS EINER ALPHA/ALPHA2 -TITANLEGIERUNG UND VERFAHREN ZU SEINER HERSTELLUNG HALF TOOL FROM AN ALPHA / ALPHA2 TITANIUM ALLOY AND METHOD FOR THE PRODUCTION THEREOF
Die Erfindung betrifft ein Halbzeug auf der Basis von α-Titan und intermetallischer Phasen des Legierungssystems Titan- Aluminium nach dem Oberbegriff des Anspruchs 1 sowie ein Verfahren zur Herstellung eines Bauteils oder einer Bauteilkomponente für einen Verbrennungsmotor nach dem Oberbegriff des Anspruchs 5.The invention relates to a semifinished product based on α-titanium and intermetallic phases of the alloy system titanium-aluminum according to the preamble of claim 1 and a method for producing a component or a component component for an internal combustion engine according to the preamble of claim 5.
Aus der DE 100 24 343 Al ist bekannt, Bauteile für Verbrennungsmotoren auf der Basis von intermetallischen γ- TiAl-Legierungen herzustellen. Diese Legierungen sind mehrphasig aufgebaut und enthalten neben dem geordneten tetragonalen γ-TiAl als Hauptphase das geordnete hexagonale ct2-Ti3Al . Sie zeichnen sich aus durch vorteilhafte mechanische und thermophysikalische Eigenschaften bei geringem spezifischem Gewicht. Der AI-Anteil dieser Legierungen liegt typischerweise bei 40-50 Atom-%.From DE 100 24 343 Al is known to produce components for internal combustion engines based on intermetallic γ- TiAl alloys. These alloys are multiphase and contain, in addition to the ordered tetragonal γ-TiAl as the main phase, the ordered hexagonal ct 2 -Ti 3 Al. They are characterized by advantageous mechanical and thermophysical properties at low specific weight. The Al content of these alloys is typically 40-50 atomic%.
Weiterhin ist aus der WO 2004/079237 A2 eine TiAl-Legierung bekannt, die sich durch einen hohen AI-Anteil auszeichnet und sich die Aushärtung durch die α2-Phase zunutze macht. Eine solche Legierung hat allerdings einen hohen Anteil an ß-Phase stabilisierenden Elementen, die sich negativ auf die Hochtemperatureigenschaften auswirken .
Ganz allgemein werden bei kommerziell erhältlichen TiAl- Legierungen durch die Zugabe von ß-Phase stabilisierenden Elementen zweiphasige Legierungen (α/ß) erzeugt, die bei niedrigen und mittleren Temperaturen eine gute Festigkeit aufweisen. Da sich die kubisch raumzentrierte ß-Phase (aufgrund eines höheren Diffusionskoeffizienten) bei höheren Temperaturen leichter verformt als die α- und α.2-Phase, ist die Hochtemperaturfestigkeit dieser Legierungen begrenzt.Furthermore, a TiAl alloy is known from WO 2004/079237 A2, which is characterized by a high Al content and makes use of the curing by the α 2 phase. However, such an alloy has a high proportion of β-phase stabilizing elements, which have a negative effect on the high-temperature properties. More generally, in the case of commercially available TiAl alloys, the addition of β-phase stabilizing elements produces biphasic alloys (α / β) which have good strength at low and medium temperatures. As the cubic body-centered ß-phase (due to a higher diffusion coefficient) deforms more easily at higher temperatures than the α- and α. 2 phase, the high temperature strength of these alloys is limited.
Der Erfindung liegt die Aufgabe zugrunde, auf der Basis des Ti-Al-Legierungssystems einen Werkstoff für Bauteile und Bauteilkomponenten in Verbrennungsmotoren vorzuschlagen, der sich durch geringes spezifisches Gewicht, eine besonders hohe Steifigkeit und große Festigkeit bei höheren Temperaturen auszeichnet. Weiterhin soll ein Verfahren zur Herstellung von Bauteilen und Bauteilkomponenten aus einem solchen Werkstoff bereitgestellt werden.The invention has for its object to propose a material for components and components components in internal combustion engines based on the Ti-Al alloy system, which is characterized by low specific gravity, a particularly high rigidity and high strength at elevated temperatures. Furthermore, a method for the production of components and component components is to be provided from such a material.
Die Aufgabe wird erfindungsgemäß durch die Merkmale der Ansprüche 1 und 5 gelöst.The object is achieved by the features of claims 1 and 5.
Danach wird zur Herstellung der Bauteile und Bauteilkomponenten ein Halbzeug aus einer α-Titanlegierung mit einem Anteil von 40-50 Vol.-% α2~Phase (Ti3Al, geordnete hexagonale Phase) und 50-60 Vol.-% α-Phase verwendet. Das Halbzeug kann außerdem bis zu 1 Vol.-% Suizide und in geringen Anteilen (bis zu 1 Vol.-% bei Betriebstemperatur) ß-Phase enthalten.Thereafter, a semifinished product of an α-titanium alloy with a proportion of 40-50 vol .-% α2 ~ phase (Ti 3 Al, ordered hexagonal phase) and 50-60 vol .-% α-phase is used to produce the components and component components , The semifinished product may additionally contain up to 1% by volume of suicides and in minor proportions (up to 1% by volume at operating temperature) of β-phase.
Der Werkstoff des Halbzeugs setzt sich vorzugsweise aus 8 - 10 Gew.-% Al; 0,2 - 5,0 Gew.-% Nb; 0,1 - 1,0 Gew.-% Mo; 0,1 - 2,0 Gew.-% Si; 0,2 - 4,0 Gew.-% Zr; 0,1 - 1,0 Gew.-% B und dem Rest Ti zusammen. Eine solche Legierung hat ein geringes spezifisches Gewicht und eine feinkörnige lamellare
Gefügestruktur. Als besonders vorteilhaft hat sich eine Zusammensetzung von 9 Gew.-% Al; 0,5 Gew.-% Nb; 0,5 Gew.-% Mo; 0,5 Gew.-% Si und den restlichen Gew.-% Ti herausgestellt.The material of the semifinished product is preferably composed of 8-10% by weight of Al; 0.2-5.0% by weight Nb; 0.1-1.0 wt% Mo; 0.1-2.0% by weight of Si; 0.2-4.0 wt% Zr; 0.1-1.0 wt% B and the balance Ti together. Such an alloy has a low specific gravity and a fine-grained lamellar Microstructure. Particularly advantageous is a composition of 9 wt .-% Al; 0.5% by weight of Nb; 0.5% by weight of Mo; 0.5 wt% Si and the remaining wt% Ti exposed.
Bauteile aus den erfindungsgemäßen α-Titanlegierungen weisen eine Streckgrenze > 1000 MPa bei Raumtemperatur, > 550 MPa bei 600° C und > 250 MPA bei 800° C auf. Ihr E-Modul liegt bei Raumtemperatur bei > 125 GPa. Da die erfindungsgemäßen Legierungen auch bei hohen Temperaturen eine erhöhte Steifigkeit und hohe Festigkeit aufweisen, eignen sie sich insbesondere als Werkstoff für Bauteile und Bauteilkomponenten in Verbrennungsmotoren, die im Betrieb hohen thermischen und mechanischen Belastungen ausgesetzt sind. Aufgrund des hohen Al-Gehalts und des geringen Anteils an schweren Legierungselementen haben die erfindungsgemäßen Legierungen eine niedrige Dichte (etwa 4.35 g/cm3). Durch den sehr niedrigen Gehalt an ß-Phase stabilisierenden Elementen wird die Ausprägung von ß-Phase unterbunden, was zu einer hohen Warmfestigkeit führt. Es bilden sich jedoch Bereiche aus, in denen eine Anreicherung an ß-Phase stabilisierenden Elementen vorliegt, was zu vielen festigkeitssteigernden inneren Grenzflächen führt. Das in der erfindungsgemäßen Legierung enthaltene Si führt zu einer effektiven Mischkristallverfestigung und bildet feine Suizide; dies hat eine Festigkeitssteigerung im gesamten Temperaturbereich zur Folge. Bei Betriebstemperatur der Motorenbauteile (d.h. zwischen 600° C und 800° C) ist die ß-Phase also unterbunden; der Anteil der α2-Phase beträgt bei 600° C vorzugsweise > 30 Vol.-% und bei 800° C vorzugsweise > 5 Vol.-%.Components made from the α-titanium alloys according to the invention have a yield strength> 1000 MPa at room temperature,> 550 MPa at 600 ° C. and> 250 MPA at 800 ° C. Its modulus of elasticity is> 125 GPa at room temperature. Since the alloys according to the invention have increased rigidity and high strength even at high temperatures, they are particularly suitable as material for components and component components in internal combustion engines which are exposed to high thermal and mechanical stresses during operation. Due to the high Al content and low content of heavy alloying elements, the alloys of the present invention have a low density (about 4.35 g / cm 3 ). Due to the very low content of ß-phase stabilizing elements, the expression of ß-phase is suppressed, resulting in a high heat resistance. However, areas are formed in which there is an accumulation of ß-phase stabilizing elements, resulting in many strength-enhancing internal interfaces. The Si contained in the alloy of the invention results in effective solid solution strengthening and forms fine suicides; This results in an increase in strength over the entire temperature range. At operating temperature of the engine components (ie between 600 ° C and 800 ° C), the ß-phase is therefore suppressed; the proportion of the α 2 phase is preferably> 30% by volume at 600 ° C. and preferably> 5% by volume at 800 ° C.
Zur Herstellung solcher Bauteile und Bauteilkomponenten werden Halbzeuge aus den erfindungsgemäßen α-Titanlegierungen
einer Warmumformung im Zustandsbereich der ß-Phase unterzogen. Die Warmumformung erfolgt vorzugsweise bei Temperaturen zwischen 1000° C und 1150° C, insbesondere zwischen 1050° C und 1110° C.For the production of such components and component parts are semi-finished products of the α-titanium alloys according to the invention subjected to hot working in the state region of the β-phase. The hot forming is preferably carried out at temperatures between 1000 ° C and 1150 ° C, in particular between 1050 ° C and 1110 ° C.
In einer vorteilhaften Ausgestaltung der Erfindung wird die α-Titanlegierung als Werkstoff für Ventile in Verbrennungsmotoren verwendet. Ausgangspunkt zur Herstellung eines solchen Ventils ist ein zylinderförmiges Halbzeug aus einer erfindungsgemäßen α-Titanlegierung, dessen Durchmesser kleiner als der Tellerdurchmesser des zu fertigenden Ventils ist. Das Halbzeug wird im Zustandsbereich der ß-Phase, vorzugsweise bei 1050° C - 1110° C, warmumgeformt. Dabei wird durch einen Strangpressvorgang der Ventilschaft ausgeformt; gleichzeitig wird durch eine Schmiedeoperation der Ventilteller ausgeformt. Auf diese Weise wird sichergestellt, dass sowohl das Material im Ventilschaft als auch das Material im Ventilteller eine Mindestumformung und dadurch die gewünschte Gefügeveränderung erfährt.In an advantageous embodiment of the invention, the α-titanium alloy is used as a material for valves in internal combustion engines. The starting point for the production of such a valve is a cylindrical semi-finished product of an α-titanium alloy according to the invention, the diameter of which is smaller than the diameter of the valve to be manufactured. The semifinished product is hot-worked in the state region of the β-phase, preferably at 1050 ° C.-1110 ° C. In this case, the valve stem is formed by an extrusion process; At the same time, the valve disk is formed by forging operation. In this way it is ensured that both the material in the valve stem and the material in the valve plate undergoes a minimum deformation and thereby the desired microstructural change.
Neben der oben beschriebenen Herstellung eines gesamten Ventils mit Hilfe der Warmumformung kann auch lediglich eine Einzelkomponente (z.B. der Ventilschaft) aus der erfindungsgemäßen α-Titanlegierung warmumgeformt werden und in einem Folgeschritt mit einer anderen Komponente (z.B. dem Ventilteller) aus demselben oder einem anderen Werkstoff verbunden werden (z.B. mittels Reibschweißen). Die erfindungsgemäße Legierung eignet sich nicht nur als Werkstoff für thermisch hochbelastete Motorenbauteile und - komponenten, sondern auch für Niedertemperaturanwendungen, bei denen besonders hohe Anforderungen in Bezug auf Steifigkeit, Festigkeit und Gewichtseinsparung gestellt werden .
Die Verwendung der erfindungsgemäßen Legierung als Ventilwerkstoff bietet die Möglichkeit höherer Motordrehzahlen und dadurch höherer Leistungen. Die Herstellung und Bearbeitung von Ventilen aus dieser Legierung erfolgt analog zu den bisher verwendeten, kommerziell erhältlichen Ventilen aus Ti-Legierungen und ist daher wesentlich einfacher und kostengünstiger als die von TiAl- Ventilen. Weiterhin ergibt sich eine höhereIn addition to the production of an entire valve by means of hot forming described above, only a single component (eg the valve stem) of the α-titanium alloy according to the invention can be hot-formed and connected in a subsequent step with another component (eg the valve disc) of the same or a different material be (eg by friction welding). The alloy according to the invention is suitable not only as a material for thermally highly stressed engine components and components, but also for low-temperature applications in which particularly high demands are made in terms of stiffness, strength and weight saving. The use of the alloy according to the invention as a valve material offers the possibility of higher engine speeds and thus higher powers. The production and processing of valves made of this alloy is analogous to the previously used, commercially available valves made of Ti alloys and is therefore much easier and less expensive than that of TiAl valves. Furthermore, there is a higher
Betriebssicherheit, da - im Unterschied zu TiAl-Legierungen - keine sprödigkeitsbedingten Ausfälle vorkommen können.Operational safety, since - in contrast to TiAl alloys - no brittleness-related failures can occur.
Im folgenden wird die Erfindung anhand eines konkretenIn the following the invention is based on a concrete
Ausführungsbeispiels näher erläutert. Dabei zeigen:Embodiment explained in more detail. Showing:
Fig. 1 eine schematische Darstellung der Gleichgewichts-1 is a schematic representation of the equilibrium
Phasenanteile der Legierung Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si in Abhängigkeit der Temperatur; Fig. 2 eine Mikrostruktur der Legierung Ti-9A1-O, 5Nb-O, 5Mo-Phase proportions of the alloy Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si as a function of the temperature; 2 shows a microstructure of the alloy Ti-9A1-O, 5Nb-O, 5Mo-
0,5Si mit bandartigen Strukturen; Fig. 3 eine Wiedergabe eines chemischen Mappings von bandartigen Strukturen in der Mikrostruktur der0.5Si with ribbon-like structures; FIG. 3 is a representation of a chemical mapping of ribbon-like structures in the microstructure of FIG
Legierung Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si in bezug auf ...Alloy Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si with respect to ...
Fig . 3a . . . Al ;Fig. 3a. , , Al;
Fig . 3b . . . S i ;Fig. 3b. , , S i;
Fig . 3c . . . Ti ;Fig. 3c. , , Ti;
Fig . 3d . . . Nb ;Fig. 3d. , , Nb;
Fig . 3e . . . Mo .Fig. 3e. , , Not a word .
Figur 1 zeigt das Ergebnis einer Modellierung der Gleichgewichts-Phasenanteile der Legierung Ti-9A1-O, 5Nb- 0,5Mo-O, 5Si in Abhängigkeit von der Temperatur; diese Legierungszusammensetzung (9 Gew.-% Al, 0,5 Gew.-% Nb, 0,5 Gew.-% Mo, 0,5 Gew.-% Si, Rest Ti) hat sich bezüglich ihrer Warmfestigkeit als besonders vorteilhaft erwiesen. Durch den niedrigen Gehalt an ß-Stabilisatoren bildet diese Legierung
die ß-Phase nicht oder in nur minimalen Volumengehalten aus. Insbesondere im Temperaturbereich zwischen 600° C und 800° C, der der Betriebstemperatur der hier betrachtetenFigure 1 shows the result of a modeling of the equilibrium phase proportions of the alloy Ti-9A1-O, 5Nb-0.5Mo-O, 5Si as a function of the temperature; this alloy composition (9% by weight Al, 0.5% by weight Nb, 0.5% by weight Mo, 0.5% by weight Si, remainder Ti) has proved to be particularly advantageous with regard to its heat resistance. Due to the low content of ß-stabilizers this alloy forms the ß-phase is not or in only minimal volume levels. Especially in the temperature range between 600 ° C and 800 ° C, the operating temperature of the considered here
Motorbauteile entspricht, liegt keine ß-Phase im Gleichgewicht vor. Trotzdem besteht eine quasi mehrphasige Gefügesubstruktur, die bei niedrigen und mittleren Temperaturen zu Eigenschaften analog zweiphasiger α/ß- Legierungen führt. Diese mehrphasige Gefügestruktur ist z.B. aus der Schuffansieht der Figur 2 ersichtlich, die die Mikrostruktur der Legierung Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si zeigt und bandartige Bereiche 1 aufweist. Wie aus dem in Figuren 3a bis 3e gezeigten chemischen Mapping - in bezug auf Al (Fig. 3a), Si (Fig. 3b), Ti (Fig. 3c), Nb (Fig. 3d) und Mo (Fig. 3e) - dieser bandartigen Bereiche 1 hervorgeht, handelt es sich in diesen Bereichen 1 um Anreicherungen von ß- Stabilisatoren . Beugungsbilder zeigen jedoch, dass in den bandartigen Bereichen 1 keine ß-Phase vorliegt.Motor components corresponds, there is no beta phase in equilibrium. Nevertheless, there is a quasi-multi-phase microstructure substructure, which leads at low and medium temperatures to properties analogous to two-phase α / ß-alloys. This multiphase microstructure is e.g. 2, which shows the microstructure of the alloy Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si and has band-like regions 1. As is apparent from the chemical mapping shown in FIGS. 3a to 3e with respect to Al (FIG. 3a), Si (FIG. 3b), Ti (FIG. 3c), Nb (FIG. 3d) and Mo (FIG. 3e). This band-like regions 1 shows that these regions 1 are enrichments of β-stabilizers. However, diffraction patterns show that there is no beta phase in the band-like regions 1.
In der erfindungsgemäßen Legierung unterbindet bei hohen Temperaturen das Fehlen der ß-Phase den ansonsten bei α/ß- Legierungen beobachteten Festigkeitseinbruch. Gleichzeitig trägt der hohe Anteil an 012-Phase zu einer Steigerung der Hochtemperaturfestigkeit bei. Ein weiterer festigkeits- steigernder Beitrag wird durch die Zugabe der 0,5 Gew.-% Si und die dadurch bedingte Mischkristallstruktur und die Ausscheidung feiner Ti5Si3-Teilchen erzielt. Insgesamt ist die Legierung Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si in Bezug auf Hochtemperaturfestigkeit und Ermüdungseigenschaften den konventionellen Ti-Legierungen deutlich überlegen und kommt denen von TiAl nahe.
In the alloy according to the invention, at high temperatures, the absence of the β-phase prevents the strength drop otherwise observed in α / β alloys. At the same time, the high proportion of 01 2 phase contributes to an increase in high-temperature strength. Another strength-increasing contribution is achieved by the addition of 0.5 wt .-% Si and the consequent mixed crystal structure and the excretion of fine Ti 5 Si 3 particles. Overall, the alloy Ti-9A1-O, 5Nb-O, 5Mo-O, 5Si is superior to the conventional Ti alloys in terms of high-temperature strength and fatigue properties and is close to those of TiAl.
Claims
1. Halbzeug auf der Basis von α-Titan und intermetallischer Phasen des Legierungssystems Titan-Aluminium, insbesondere zur Verwendung als Bauteil oder Bauteilkomponente in einem Verbrennungsmotor, dadurch gekennzeichnet, dass das Halbzeug die folgende Phasenzusammensetzung hat:Semi-finished product based on α-titanium and intermetallic phases of the titanium-aluminum alloy system, in particular for use as a component or component component in an internal combustion engine, characterized in that the semi-finished product has the following phase composition:
40 - 50 Vol.-% α2-Phase (Ti3Al),40-50 vol.% Α 2 -phase (Ti 3 Al),
< 1 Vol.-% Suizide<1% by volume of suicides
≤ 1 Vol.-% ß-Phase und≤ 1 vol.% Β-phase and
- Rest α-Phase.- Rest α-phase.
2. Halbzeug nach Anspruch 1, dadurch gekennzeichnet, dass das Halbzeug die folgende chemische Zusammensetzung hat:2. Semifinished product according to claim 1, characterized in that the semifinished product has the following chemical composition:
- 8 - 10 Gew.-% Al,- 8 - 10 wt .-% Al,
- 0,2 - 5,0 Gew.-% Nb,0.2 to 5.0% by weight of Nb,
- 0,1 - 1,0 Gew.-% Mo,0.1 to 1.0 wt% Mo,
- 0,1 - 2,0 Gew.-% Si,0.1 to 2.0% by weight of Si,
- 0,2 - 4,0 Gew.-% Zr,0.2 to 4.0% by weight Zr,
- 0,1 - 1,0 Gew.-% B und0.1-1.0 wt% B and
- Rest Ti. - rest Ti.
3. Halbzeug nach Anspruch 2, dadurch gekennzeichnet, dass das Halbzeug die folgende chemische Zusammensetzung hat:3. Semi-finished product according to claim 2, characterized in that the semi-finished product has the following chemical composition:
- etwa 9 Gew.-% Al,about 9% by weight of Al,
- etwa 0,5 Gew.-% Nb,about 0.5% by weight of Nb,
- etwa 0,5 Gew.-% Mo,about 0.5% by weight of Mo,
- etwa 0,5 Gew.-% Si, und- About 0.5 wt .-% Si, and
- Rest Ti.- rest Ti.
4. Verwendung eines Halbzeugs nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass das Halbzeug zur Herstellung eines Ventils für einen Verbrennungsmotor verwendet wird.4. Use of a semifinished product according to one of claims 1 to 3, characterized in that the semifinished product is used for producing a valve for an internal combustion engine.
5. Verfahren zur Herstellung eines Bauteils oder einer Bauteilkomponente aus einer Titan-Aluminium-Legierung für einen Verbrennungsmotor, dadurch gekennzeichnet, dass das Bauteil oder die Bauteilkomponente durch eine Warmumformung eines Halbzeugs nach Anspruch 1 oder 2 im5. A method for producing a component or a component component made of a titanium-aluminum alloy for an internal combustion engine, characterized in that the component or the component component by a hot deformation of a semifinished product according to claim 1 or 2 in the
Zustandsbereich der ß-Phase hergestellt wird.State region of the ß-phase is produced.
6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, dass die Warmumformung in einem Temperaturbereich zwischen 1000° C und 1150° C, insbesondere zwischen 1050° C und 1110° C, erfolgt.6. The method according to claim 5, characterized in that the hot forming in a temperature range between 1000 ° C and 1150 ° C, in particular between 1050 ° C and 1110 ° C, takes place.
7. Verfahren nach Anspruch 6, dadurch gekennzeichnet, dass die Warmumformung eine Schmiedeoperation umfasst.7. The method according to claim 6, characterized in that the hot forming comprises a forging operation.
8. Verwendung des Verfahrens nach einem der Ansprüche 5 bis 7 zur Herstellung eines Ventils mit einem Ventilschaft und einem Ventilteller, wobei, ausgehend von einem zylinderförmigen Halbzeug aus einer α-Titanlegierung des Systems Titan-Aluminium, das Ventil durch einen Warmumformvorgang hergestellt wird, bei dem mittels Strangpressen der Ventilschaft und gleichzeitig mittels Schmieden der Ventilteller erzeugt wird. 8. Use of the method according to any one of claims 5 to 7 for the manufacture of a valve with a valve stem and a valve disk, wherein, starting from a cylindrical semi-finished product of an α-titanium alloy of the system titanium-aluminum, the Valve is produced by a hot forming process, wherein the valve stem is produced by extrusion of the valve stem and simultaneously by forging.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102006002377 | 2006-01-17 | ||
| DE102006002377.3 | 2006-01-17 | ||
| DE102006052650A DE102006052650A1 (en) | 2006-01-17 | 2006-11-08 | Α / α2 titanium alloy valve and method of making the same |
| DE102006052650.3 | 2006-11-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2007082708A1 true WO2007082708A1 (en) | 2007-07-26 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2007/000322 WO2007082708A1 (en) | 2006-01-17 | 2007-01-16 | Semifinished part composed of an alpha/alpha2-titanium alloy and process for producing it |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE102006052650A1 (en) |
| WO (1) | WO2007082708A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010086372A1 (en) | 2009-01-28 | 2010-08-05 | Intelligent Solutions Technology Limited | Titanium alloy, a method of producing the alloy and an article made of the alloy |
| CN115852286A (en) * | 2022-12-27 | 2023-03-28 | 西安理工大学 | Method for optimizing fracture toughness of TC11 and TC17 dissimilar titanium alloy linear friction welding joint |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3269838B1 (en) | 2016-07-12 | 2021-09-01 | MTU Aero Engines AG | High temperature resistant tial alloy, method for production of a composent from a corresponding tial alloy, component from a corresponding tial alloy |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB873774A (en) * | 1958-09-08 | 1961-07-26 | Ici Ltd | Titanium alloys |
| US5849112A (en) * | 1994-11-15 | 1998-12-15 | Boeing North American, Inc. | Three phase α-β titanium alloy microstructure |
| WO2004079237A2 (en) * | 2003-01-23 | 2004-09-16 | Limited Liability Company 'components Of Engine' | Valve for internal combustion engine, its method of manufacturing, and the high-temperature titanium alloy for the valve |
-
2006
- 2006-11-08 DE DE102006052650A patent/DE102006052650A1/en not_active Withdrawn
-
2007
- 2007-01-16 WO PCT/EP2007/000322 patent/WO2007082708A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB873774A (en) * | 1958-09-08 | 1961-07-26 | Ici Ltd | Titanium alloys |
| US5849112A (en) * | 1994-11-15 | 1998-12-15 | Boeing North American, Inc. | Three phase α-β titanium alloy microstructure |
| WO2004079237A2 (en) * | 2003-01-23 | 2004-09-16 | Limited Liability Company 'components Of Engine' | Valve for internal combustion engine, its method of manufacturing, and the high-temperature titanium alloy for the valve |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010086372A1 (en) | 2009-01-28 | 2010-08-05 | Intelligent Solutions Technology Limited | Titanium alloy, a method of producing the alloy and an article made of the alloy |
| CN115852286A (en) * | 2022-12-27 | 2023-03-28 | 西安理工大学 | Method for optimizing fracture toughness of TC11 and TC17 dissimilar titanium alloy linear friction welding joint |
| CN115852286B (en) * | 2022-12-27 | 2023-11-24 | 西安理工大学 | Optimizing method for fracture toughness of TC11 and TC17 dissimilar titanium alloy linear friction welding joint |
Also Published As
| Publication number | Publication date |
|---|---|
| DE102006052650A1 (en) | 2007-07-19 |
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