Method for improving high-temperature toughness of disc shaft parts
By combining low-speed near-yield temperature setting with solution treatment and cyclic torsional deformation, the problem of balancing high-temperature strength, toughness, and thermoplasticity in disc-shaped parts was solved, thereby improving high-temperature strength and toughness and reducing process costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTHWESTERN POLYTECHNICAL UNIV
- Filing Date
- 2025-01-03
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies struggle to improve the high-temperature strength and toughness of disc-shaped parts while maintaining or even enhancing the thermoplasticity of the metal material, and simultaneously coordinating the internal stress distribution. Furthermore, traditional processes are costly and require sophisticated equipment.
The process involves low-speed near-yield temperature setting combined with solution treatment, followed by cyclic torsional deformation at a fixed temperature to prestress, eliminating temperature gradients, and then cyclic torsional deformation on the metal shaft blank. The blank is then cooled to room temperature to form a high-temperature, high-toughness shaft.
It significantly improves the high-temperature strength and toughness of disc-shaped parts, reduces process costs, avoids the problem of high equipment requirements in traditional processes, and maintains or enhances the thermoplasticity of materials.
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Figure CN119710195B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to metal material strengthening technology, and more particularly to a method for improving the high-temperature strength and toughness of disc-shaped components. Specifically, it is a method for improving the overall thermal performance of rotating components by comprehensively utilizing heat treatment and low-speed near-yield temperature setting processes. Background Technology
[0002] The development of advanced aviation technology demands continuous improvement in the strength, lifespan, and reliability of components in aero-engine gas turbines. Disc-type parts are key components of gas turbine engines, including fan discs, compressor discs, turbine discs, drum-shaped reinforcing discs, gear discs, and various rotating components such as gear shafts and power shafts. The performance of these discs plays a crucial role in the service performance indicators of aero-engines, such as thrust-to-weight ratio, lifespan, reliability, and safety.
[0003] Gas turbines and turbojet engines operate under harsh conditions. Their internal rotating parts are subjected to a combination of centrifugal force, thermal stress, and vibration stress, resulting in highly complex stress states and exceptionally severe operating conditions. Different types of discs and shafts, as well as different parts thereof, experience significant variations in temperature, mechanical loads, and media effects. Since major engine components are typically made of high-value metallic materials with excellent overall performance, the design process generally fully explores the structural and strength potential of each component to achieve advanced overall engine performance while considering the potential of existing materials. This involves reducing strength margins and conducting reliability analysis to lower overall design and manufacturing costs.
[0004] Traditional disc shaft parts are often strengthened by methods such as solution aging or deformation heat treatment. For example, application numbers CN202211715644.X "Heat treatment method for high temperature alloy disc shaft forgings and the obtained disc shaft forgings" and CN202311582543.4 "A preparation method for TC6 titanium alloy blade forgings of aero-engines" provide solution aging and deformation heat treatment processes, respectively. Both processes can improve the strength and toughness of engine disc shaft parts to a certain extent, and the shape of the parts will also change further during the processing.
[0005] Overspeed treatment of disc-shaped shaft parts before service can induce strain hardening, improving room temperature and high temperature tensile yield strength, fatigue life, and crack propagation life while maintaining the cross-section of the disc-shaped shaft parts. As described in applications CN202321631195.0 "A Workbench for Overspeed Testing" and CN201821311850.3 "An Impeller Overspeed Testing Device," these overspeed tuning processes place extremely high demands on the rigidity and alignment of the equipment. During overspeed rotation, it is difficult to utilize multi-physics coupling to strengthen the workpiece, and the internal stress of the workpiece cannot be precisely controlled and distributed, resulting in high technological difficulty and cost. Summary of the Invention
[0006] The purpose of this invention is to overcome the problems existing in the prior art and provide a method to improve the high-temperature strength and toughness of disc shaft parts. While improving the thermal strength of the metal material, it ensures that its thermoplasticity does not decrease significantly or even increases, and simultaneously coordinates the improvement of the material's thermal strength and thermoplasticity, thereby adjusting the internal stress distribution of the parts.
[0007] To achieve the above, the technical solution adopted by the present invention is: a method for improving the high-temperature strength and toughness of disc-shaped components, the specific steps of which are as follows:
[0008] Step 1, Pre-heat treatment:
[0009] The metal shaft blank is solution treated to eliminate residual stress inside the blank, thus obtaining a pretreated blank.
[0010] Step 2, low-speed near-yield temperature tuning:
[0011] After eliminating the temperature gradient of the pretreated shaft blank, keep the temperature constant and apply prestress to near yield. Then, perform cyclic torsional deformation on one end of the pretreated shaft blank, that is, twist one end of the shaft blank in one direction until the entire shaft blank is deformed, and then immediately twist it in the opposite direction until the entire shaft blank is deformed. Repeat this cyclic torsional deformation for 2-8 hours at a fixed temperature.
[0012] Among them, the treatment temperature for eliminating the temperature gradient of the pretreated shaft blank is determined based on the material of the metal shaft blank; in the cyclic torsional deformation, the fixed temperature and torsional speed are determined on the premise that the material of the metal shaft blank will not break due to excessive torsional speed.
[0013] Step 3: Fabrication of high-temperature high-strength and tough disks and shafts:
[0014] After the cyclic torsional deformation is completed, it is cooled to room temperature, and the deformed section is directly taken to obtain a shaft with high temperature strength and toughness, or the deformed section is cut off and processed into a disc of the corresponding shape.
[0015] Furthermore, in step one, the solution treatment temperature is determined according to the material of the metal shaft blank; when the metal shaft blank is a two-phase titanium alloy material, the solution temperature is 40~100℃ below the β phase transformation point, the solution holding time is 0.5~2h, and the cooling method is water cooling or air cooling.
[0016] Furthermore, in step two, prestress is applied to one end of the pretreated shaft blank, followed by cyclic torsion; wherein, the prestress is tensile stress or compressive stress and is less than the yield strength of the metal shaft blank.
[0017] Furthermore, the prestress is 30–50 MPa.
[0018] Furthermore, in step two, the angle of the cyclic torsional deformation is 30 to 60°; the torsional speed of the cyclic torsional deformation is 1 to 5 revolutions / min.
[0019] Furthermore, in step two, the duration of one cyclic torsional deformation cycle is 6~24s.
[0020] Furthermore, the cooling described in step three is air cooling.
[0021] Furthermore, in step two, the fixed temperature during cyclic torsional deformation is 50~400℃ below the conventional aging temperature of the metal shaft blank.
[0022] Furthermore, the fixed temperature during the cyclic torsional deformation is 200°C below the conventional aging temperature of the metal shaft blank.
[0023] Furthermore, the metal shaft blank for the disc or shaft type is TC11 or Ti643 titanium alloy.
[0024] The beneficial effects of this invention are as follows: This invention couples low-speed near-yield tuning with solution aging, and combines solution strengthening, deformation strengthening, aging strengthening and grain refinement strengthening. It utilizes repeated shear deformation to promote dislocation rearrangement, form diffusion pathways, thereby reducing the aging temperature and enhancing the tuning effect. This breaks the constraint of traditional heat treatment processes that rely solely on aging strengthening to only improve the thermal strength of metallic materials. It can significantly improve the strength and toughness of metallic materials without losing or even improving their thermoplasticity, enabling them to meet more demanding service conditions.
[0025] Compared to the high-speed tuning process for aero-engine discs and shafts, this method does not require expensive equipment. Compared to traditional aging processes, it does not require higher temperatures or longer durations. Compared to traditional mechanical heat treatment (deformation-coupled heat treatment), it can simultaneously improve high-temperature strength and toughness. While improving the thermal strength of metallic materials, it ensures that their thermoplasticity does not decrease significantly or even increases, thus coordinating the improvement of thermal strength and thermoplasticity, tuning the internal stress distribution of components, and significantly reducing process costs. Attached Figure Description
[0026] Figure 1 This is a process flow diagram of the present invention;
[0027] Figure 2 This is a schematic diagram of the process of the present invention;
[0028] Figure 3 This is a schematic diagram of a specific example of a deformed metal specimen.
[0029] In the figure: 1-sample shaft, 2-transition arc surface, 3-auxiliary clamping shaft, 4-transition shaft, 5-compression stop shaft, 6-tension stop, 7-torsion shaft;
[0030] Figure 4 These are the tensile stress-strain curves at 600℃ for specific examples 1 and 2 of the present invention and comparative example 1.
[0031] Figure 5 These are the high-temperature tensile stress-strain curves at 600℃ for specific examples 1, 3, and 4 of the present invention and comparative example 1.
[0032] Figure 6 These are the tensile stress-strain curves at 600℃ for specific examples 1 and 5 of the present invention and comparative example 1.
[0033] Figure 7 The figures are the high-temperature tensile stress-strain curves at 600℃ for specific examples 6 and 7 of the present invention and comparative example 2. Detailed Implementation
[0034] The technical solution of the present invention will now be described in detail and completely with reference to the accompanying drawings. However, the embodiments described below are only some embodiments of the present invention, and not all embodiments.
[0035] Example 1: As Figure 1 As shown, a method for improving the high-temperature strength and toughness of disc-shaped components includes the following specific steps:
[0036] Step 1, Pre-heat treatment:
[0037] The metal shaft blank is solution treated to eliminate residual stress inside the blank, thus obtaining a pretreated blank.
[0038] The solution treatment temperature is determined based on the material of the metal shaft blank;
[0039] Step 2, low-speed near-yield temperature tuning:
[0040] After eliminating the temperature gradient of the pretreated shaft blank, keep the temperature constant and apply prestress to near yield. Then, perform cyclic torsional deformation on one end of the pretreated shaft blank, that is, twist one end of the shaft blank in one direction until the entire shaft blank is deformed, and then immediately twist it in the opposite direction until the entire shaft blank is deformed. Repeat this cyclic torsional deformation for 2-8 hours at a fixed temperature.
[0041] Among them, the treatment temperature for eliminating the temperature gradient of the pretreated shaft blank is determined based on the material of the metal shaft blank; in the cyclic torsional deformation, the fixed temperature and torsional speed are determined on the premise that the material of the metal shaft blank will not break due to excessive torsional speed.
[0042] Step 3: Fabrication of high-temperature high-strength and tough disks and shafts:
[0043] After the cyclic torsional deformation is completed, the parts are air-cooled to room temperature, and the deformed section is directly taken to obtain a shaft with high temperature strength and toughness, or the deformed section is cut off and processed into a disc of the corresponding shape.
[0044] The blanks for discs or shafts are made of TC11 or Ti643 titanium alloy.
[0045] Example 2: Same as Example 1, except that in step one, when the metal shaft blank is a two-phase titanium alloy material, the solution temperature is 40~100℃ below the β phase transformation point, the solution holding time is 0.5~2h, and the cooling method is water cooling or air cooling.
[0046] Example 3: Same as Example 1, except that in step two, prestress is applied to one end of the pretreated shaft blank, and then cyclic torsion is performed;
[0047] The prestress is either tensile or compressive and is less than the yield strength of the metal shaft blank. The prestress is 30–50 MPa.
[0048] Example 4: Same as Example 1, except that in step two, the angle of the cyclic torsional deformation is 30 to 60°; the torsional speed is 1 to 5 cycles / min; and the duration of one cyclic torsional deformation cycle is 6 to 24 seconds.
[0049] The fixed temperature for cyclic torsional deformation is 50~400℃ below the conventional aging temperature of the metal shaft blank.
[0050] Example 5: Same as Example 4, except that the fixed temperature during cyclic torsional deformation is 200°C below the conventional aging temperature of the metal shaft blank.
[0051] like Figure 2-7 As shown, to further illustrate the technical solution and beneficial effects of the present invention, the present invention provides the following specific examples and comparative examples:
[0052] First, let's explain the structure of the sample used in the specific example: (e.g.) Figure 2 , Figure 3 As shown,
[0053] like Figure 3 As shown, the entire specimen is machined into a single unit using a CNC lathe. One end of the specimen shaft 1 is connected to the transition shaft 4 via an arc surface 2. The end of the transition shaft 4 is fixed to the auxiliary clamping shaft 3, and the end of the auxiliary clamping shaft 3 is machined with a tensile flange 6. The other end of the specimen shaft 1 is connected to the compression stop shaft 5, and the end of the compression stop shaft 5 is connected to the torsion shaft 7. The diameters of the transition shaft 4 and the compression stop shaft 5 are both larger than those of the auxiliary clamping shaft 3 and the compression stop shaft 5, while the diameter of the specimen shaft 1 is smaller than that of the transition shaft 4 and the compression stop shaft 5. The circumferences of the auxiliary clamping shaft 3 and the torsion shaft 7 are each machined with three planes distributed at 120°, which are used for tensile clamping, compression clamping, and torsion clamping of the specimen, respectively.
[0054] How to use:
[0055] A three-jaw chuck is used to fix three torsional planes distributed at 120° on the auxiliary clamping shaft 3. When tensile stress is applied, the tension stop 6 provides a fixing function; when compressive stress is applied, the compression stop 5 provides a fixing function. Figure 3 As shown, during deformation, the applied prestress causes the jaws to press against the tensile flange 6 or the compression flange 5, thereby applying tensile / compressive stress. During torsion, the three jaws clamp the three torsion planes distributed at 120° on the torsion shaft 7, cyclically torturing to achieve positive and negative torsion deformation of the specimen. The specimen shaft 1 is heated by a heating coil, and the deformation temperature is monitored in real time by a thermocouple. The processing procedure is as follows: Figure 2 As shown.
[0056] Specific example 1:
[0057] A method for improving the high-temperature strength and toughness of disc-shaped components includes the following steps:
[0058] (1) The TC11 titanium alloy to be treated was pre-solution treated in the two-phase region at a temperature of 950°C and held for 1 hour before being cooled to room temperature in air.
[0059] (2) The TC11 titanium alloy sample after pre-solution treatment is clamped on a low-speed near yield temperature setting tester, heated to 200℃, and held for 10 minutes to ensure the elimination of temperature gradient.
[0060] (3) Keep the temperature constant and preload it with tensile stress of 50 MPa. Then carry out cyclic torsional deformation at a torsion speed of 2 cycles / min and a torsion angle of 30° forward and then immediately reverse 30°. The duration of one cycle is 9s. After setting the low speed near the yield temperature for 4 hours, stop the deformation and heating and air cool to room temperature.
[0061] The mechanical properties of the treated TC11 titanium alloy samples were tested, and the results are shown in Table 1.
[0062] Stress-strain curves are shown Figure 4 .
[0063] Performance testing instructions: The high-temperature tensile test was conducted on an Instron 3382 electronic universal testing machine, and the high-temperature tensile mechanical properties were tested in accordance with GB / T228.2-2015 "Metallic materials, tensile testing - Part 2: High-temperature test method".
[0064] Comparative Example 1:
[0065] The heat treatment process for solution aging of TC11 material involves first holding the material at 950℃ for 1 hour and then air cooling, followed by holding it at 530℃ for 6 hours and then cooling it to room temperature in air.
[0066] The mechanical properties of the treated TC11 material were tested, and the results are shown in Table 1. The stress-strain curves are shown in Table 1. Figure 4 .
[0067] Specific example 2:
[0068] A method for improving the high-temperature strength and toughness of disc-shaped components includes the following steps:
[0069] (1) The TC11 titanium alloy to be treated was pre-solution treated in the two-phase region at a temperature of 950℃ and held for 1 hour before being quenched in water to room temperature.
[0070] (2) The TC11 titanium alloy sample after pre-solution treatment is clamped on a low-speed near yield temperature setting tester, heated to 200℃, and held for 10 minutes to ensure the elimination of temperature gradient.
[0071] (3) Keep the temperature constant and preload it with tensile stress of 50 MPa. Then carry out cyclic torsional deformation at a torsion speed of 3 cycles / min and a torsion angle of 30° forward and then immediately reverse 30°. The duration of one cycle is 9s. After setting the low speed near the yield temperature for 4 hours, stop the deformation and heating and air cool to room temperature.
[0072] The mechanical properties of the treated TC11 titanium alloy samples were tested, and the results are shown in Table 1.
[0073] Stress-strain curves are shown Figure 4 .
[0074] Specific example 3:
[0075] A method for improving the high-temperature strength and toughness of disc-shaped components includes the following steps:
[0076] (1) The TC11 titanium alloy to be treated was pre-solution treated in the two-phase region at a temperature of 950°C and held for 1 hour before being cooled to room temperature in air.
[0077] (2) The TC11 titanium alloy sample after pre-solution treatment is clamped on a low-speed near yield temperature setting tester, heated to 200℃, and held for 10 minutes to ensure the elimination of temperature gradient.
[0078] (3) Keep the temperature constant and preload it with compressive stress of 50 MPa. Then carry out cyclic torsional deformation at a torsional speed of 2 cycles / min and a torsional angle of 30° forward and then immediately reverse 30°. The duration of one cycle is 9s. After setting the low speed near the yield temperature for 4 hours, stop the deformation and heating and air cool to room temperature.
[0079] The mechanical properties of the treated TC11 titanium alloy samples were tested, and the results are shown in Table 1.
[0080] Stress-strain curves are shown Figure 5 .
[0081] Specific example 4:
[0082] A method for improving the high-temperature strength and toughness of disc-shaped components includes the following steps:
[0083] (1) The TC11 titanium alloy to be treated was pre-solution treated in the two-phase region at a temperature of 950°C and held for 1 hour before being cooled to room temperature in air.
[0084] (2) The TC11 titanium alloy sample after pre-solution treatment is clamped on a low-speed near yield temperature setting tester, heated to 200℃, and held for 10 minutes to ensure the elimination of temperature gradient.
[0085] (3) Keep the temperature constant, do not apply prestress, and directly carry out cyclic torsion deformation. The torsion speed is 4 cycles / min, the torsion angle is 30° forward and then immediately reversed by 30°. The duration of one cycle is 9s. After setting the low speed near the yield temperature for 4 hours, stop the deformation and heating, and air cool to room temperature.
[0086] The mechanical properties of the treated TC11 titanium alloy samples were tested, and the results are shown in Table 1. The stress-strain curves are shown in Table 1. Figure 5 .
[0087] Specific example 5:
[0088] A method for improving the high-temperature strength and toughness of disc-shaped components includes the following steps:
[0089] (1) The TC11 titanium alloy to be treated was pre-solution treated in the two-phase region. The solution treatment regime was 950℃, and after holding for 1 hour, it was cooled to room temperature in air.
[0090] (2) The TC11 titanium alloy sample after pre-solution treatment is clamped on a low-speed near yield temperature setting tester, heated to 200℃, and held for 10 minutes to ensure the elimination of temperature gradient.
[0091] (3) Keep the temperature constant and preload it with tensile stress of 50 MPa. Then carry out cyclic torsional deformation at a torsion speed of 1 revolution / min and a torsion angle of 10° forward and then immediately reverse 10°. The duration of one cycle is 5s. After setting at low speed near the yield temperature for 4 hours, stop the deformation and heating and air cool to room temperature.
[0092] The mechanical properties of the treated TC11 titanium alloy samples were tested, and the results are shown in Table 1. The stress-strain curves are shown in Table 1. Figure 6 .
[0093] Specific example 6:
[0094] A method for improving the high-temperature strength and toughness of disc-shaped components includes the following steps:
[0095] (1) The Ti643 titanium alloy to be treated was pre-solution treated in the two-phase region at a temperature of 970℃. After holding at the temperature for 1 hour, it was cooled to room temperature in air.
[0096] (2) The pre-solution treated Ti643 titanium alloy sample was clamped on a low-speed near-yield temperature setting tester, heated to 200℃, and held for 10 minutes to ensure the elimination of temperature gradient;
[0097] (3) Keep the temperature constant, do not apply prestress, and directly carry out cyclic torsion deformation. The torsion speed is 3 cycles / min, the torsion angle is 30° forward and then immediately reversed by 30°. The duration of one cycle is 9s. After setting the low speed near the yield temperature for 4 hours, stop the deformation and heating, and air cool to room temperature.
[0098] The mechanical properties of the treated Ti643 titanium alloy samples were tested, and the results are shown in Table 1. The stress-strain curves are shown in Table 1. Figure 7 .
[0099] Comparative Example 2:
[0100] The solution-aging heat treatment process for Ti643 material involves first holding the material at 970℃ for 1 hour and then air-cooling it, followed by holding it at 650℃ for 4 hours and then cooling it to room temperature in air.
[0101] The mechanical properties of the treated Ti643 material were tested, and the results are shown in Table 1. The stress-strain curves are shown in Table 1. Figure 7 .
[0102] Specific example 7:
[0103] A method for improving the high-temperature strength and toughness of disc-shaped components includes the following steps:
[0104] (1) The Ti643 titanium alloy to be treated was pre-solution treated in the two-phase region at a temperature of 970℃. After holding at the temperature for 1 hour, it was cooled to room temperature by water.
[0105] (2) The pre-solution treated Ti643 titanium alloy sample was clamped on a low-speed near-yield temperature setting tester, heated to 200℃, and held for 10 minutes to ensure the elimination of temperature gradient;
[0106] (3) Keep the temperature constant, do not apply prestress, and directly carry out cyclic torsion deformation. The torsion speed is 3 cycles / min, the torsion angle is 30° forward and then immediately reversed by 30°. The duration of one cycle is 9s. After setting the low speed near the yield temperature for 4 hours, stop the deformation and heating, and air cool to room temperature.
[0107] The mechanical properties of the treated Ti643 titanium alloy samples were tested, and the results are shown in Table 1. The stress-strain curves are shown in Table 1. Figure 7 .
[0108] Table 1. Mechanical property test results
[0109]
[0110] Combining Table 1 and Figures 4-7 It can be seen that, compared with the traditional solution aging heat treatment process, the high-temperature mechanical properties such as high-temperature yield strength, tensile strength and elongation are significantly improved after the process of this invention, while the reduction of area also increases slightly.
[0111] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for improving the high-temperature strength and toughness of disc-shaped components, characterized in that, The specific steps are as follows: Step 1, Pre-heat treatment: The metal shaft blank is subjected to solution treatment to eliminate residual stress inside the blank, and a pre-treated blank is obtained; Step 2, low-speed near-yield temperature tuning: After eliminating the temperature gradient of the pretreated shaft blank, the temperature is kept constant, and prestress is applied until near yield. Then, prestress is applied to one end of the pretreated shaft blank to perform cyclic torsional deformation, that is, torsion is performed by twisting one end of the shaft blank in one direction until the entire shaft blank is deformed, and then immediately twisted in the opposite direction until the entire shaft blank is deformed. This cyclic torsional deformation is performed for 2-8 hours at a fixed temperature. The treatment temperature for eliminating the temperature gradient of the pretreated shaft blank is determined based on the material of the metal shaft blank. In the cyclic torsional deformation, a fixed temperature and torsional speed are determined under the premise that the material of the metal shaft blank will not fracture due to excessive torsional speed. The prestress is tensile or compressive stress and is less than the yield strength of the metal shaft blank material, with a prestress of 30–50 MPa. The angle of the cyclic torsional deformation is 30–60 degrees. The torsional speed of the cyclic torsional deformation is 1–5 revolutions / min. The duration of one cyclic torsional deformation cycle is 6–24 seconds. Step 3: Fabrication of high-temperature high-strength and tough disks and shafts: After the cyclic torsional deformation is completed, it is cooled to room temperature, and the deformed section is directly taken to obtain a shaft with high temperature strength and toughness, or the deformed section is cut off and processed into a disc of the corresponding shape. The metal shaft blank is TC11 or Ti643 titanium alloy.
2. The method for improving the high-temperature strength and toughness of disc-shaped components according to claim 1, characterized in that, In step one, the solution treatment temperature is determined according to the material of the metal shaft blank; when the metal shaft blank is a two-phase titanium alloy, the solution temperature is 40~100℃ below the β phase transformation point, the solution holding time is 0.5~2h, and the cooling method is water cooling or air cooling.
3. The method for improving the high-temperature strength and toughness of disc-shaped components according to claim 1, characterized in that, The cooling described in step three is air cooling.
4. The method for improving the high-temperature strength and toughness of disc-shaped components according to claim 1, characterized in that, In step two, the fixed temperature during the cyclic torsional deformation is 50~400℃ below the conventional aging temperature of the metal shaft blank.
5. The method for improving the high-temperature strength and toughness of disc-shaped components according to claim 4, characterized in that, The fixed temperature during cyclic torsional deformation is 200°C below the conventional aging temperature of the metal shaft blank.