A high-temperature alloy and a method for producing the same

Abstract

The application discloses a high-temperature alloy and a preparation method thereof, and belongs to the technical field of high-temperature alloys, and aims to solve the problem of low creep resistance of the existing high-temperature alloy at 780 DEG C. The mass fraction of each element of the high-temperature alloy comprises the following: C 0.06% to 0.07%, Co 17.0% to 19.0%, Cr 9.0% to 11.0%, Mo 2.3% to 2.7%, W 3.4% to 4.8%, Ta 2.9% to 4.5%, Al 3.45% to 3.8%, Ti 3.25% to 3.6%, Nb 1.2% to 1.8%, Hf 0.2% to 0.4%, Zr 0.04% to 0.06%, B 0.03% to 0.05%, Mg 0.002% to 0.010%, and the balance of Ni. The high-temperature alloy has high creep resistance at 780 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature alloy technology, specifically relating to a nickel-based powder high-temperature alloy that can be used at temperatures above 780°C and its preparation method. Background Technology

[0002] Turbine disks are one of the most important hot-end components in engines. During service, turbine disk alloys are required to possess not only high tensile strength but also excellent high-temperature creep resistance, minimal tendency for topologically packed (TCP) phase precipitation, and good high-temperature microstructural stability. Existing high-temperature alloys for turbine disks, such as FGH4098, have a maximum service temperature limit of 750°C. Above 750°C, creep resistance decreases, and severe TCP phase formation occurs, failing to meet the creep performance requirements at 780°C. Summary of the Invention

[0003] In view of the above analysis, the present invention aims to provide a high-temperature alloy and its preparation method to solve the following technical problem: existing high-temperature alloys have low creep resistance when used at temperatures above 750°C.

[0004] The objective of this invention is mainly achieved through the following technical solutions:

[0005] On one hand, the present invention provides a high-temperature alloy, wherein the mass fraction of each element in the high-temperature alloy comprises: C 0.06%–0.07%, Co 17.0%–19.0%, Cr 9.0%–11.0%, Mo 2.3%–2.7%, W 3.4%–4.8%, Ta 2.9%–4.5%, Al 3.45%–3.8%, Ti 3.25%–3.6%, Nb 1.2%–1.8%, Hf 0.2%–0.4%, Zr 0.04%–0.06%, B 0.03%–0.05%, Mg 0.002%–0.010%, and the balance Ni.

[0006] Furthermore, the mass fraction ratio of (C+Ti) / (Ti+Nb+Ta+Hf) is 0.30 to 0.50.

[0007] Furthermore, the total mass fraction of Co, Cr, Mo, and W is 32.0% to 37.0%.

[0008] Furthermore, the total mass fraction of W and Ta is 7.0% to 8.0%.

[0009] Furthermore, the mass fraction ratio of Ta to W, Ta / W, is 0.6 to 1.3.

[0010] Furthermore, the total mass fraction of Al, Ti, Nb, Ta, and Hf is 11.0% to 14.0%.

[0011] Furthermore, the total mass fraction of Al and Ti is 6.8% to 7.2%.

[0012] Furthermore, the microstructure of the high-temperature alloy includes a γ matrix phase and precipitated phases, with a uniform structure and dispersed precipitated phases. The precipitated phases mainly include the γ′ phase, MC-type carbides, and M3B2-type borides. The γ′ phase is of the (Ni,Co)3(Al,Ti,Ta,Nb,W,Hf) type, and the MC-type carbides are of the (Ti,Ta,Nb,Hf)C type. The element Ta is mainly distributed in the γ′ phase, while the element Mg enters the γ matrix phase and segregates at the grain boundaries.

[0013] This invention also provides a method for preparing a high-temperature alloy, comprising the following steps:

[0014] Step 1: Prepare the alloy using vacuum induction melting process according to the mass fraction ratio, and obtain alloy bars;

[0015] Step 2: The alloy rod is powdered, sieved, and electrostatically treated using the plasma rotating electrode method to obtain alloy powder with a diameter of 50μm to 150μm.

[0016] Step 3: Under vacuum conditions, the alloy powder is loaded into a low-carbon steel sleeve, degassed and sealed, and then hot isostatically pressed to obtain an ingot.

[0017] Step 4: Heat treat the ingot, including solution treatment and aging treatment, to obtain a high-temperature alloy with high creep resistance.

[0018] Furthermore, in step 4, the solution treatment process parameters are: 1190℃~1220℃ / 2h~6h / air cooling, and the aging treatment process parameters are: 790℃~820℃ / 4h~16h / air cooling.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] a) This invention strengthens the alloy by adding solid solution strengthening elements (Co, Cr, Mo, W), γ′ phase forming elements (Al, Ti, Nb, Ta, Hf), and grain boundary strengthening elements (B, Zr, Mg); by adding high (W+Ta) content and appropriate amount of element Mg, combined with coarse grains, the alloy achieves excellent high-temperature creep resistance, thereby obtaining a composition range with good comprehensive mechanical properties.

[0021] b) In the high-temperature alloy of the present invention, by controlling the ratio of (C+Ti) / (Ti+Nb+Ta+Hf) content and by coordinating the control of the content of elements such as Co, Cr, Mo, W, and Ta, the tendency of TCP phase precipitation is reduced, the high-temperature microstructure stability of the alloy is improved, and the alloy has a higher maximum operating temperature.

[0022] c) The microstructure of the high-temperature alloy of the present invention includes a γ matrix phase and precipitated phases, with a uniform structure and dispersed precipitated phases. The precipitated phases mainly include γ′ phase, MC-type carbides, and M3B2-type borides. The γ′ phase is of the (Ni,Co)3(Al,Ti,Ta,Nb,W,Hf) type, and the MC-type carbides are of the (Ti,Ta,Nb,Hf)C type. Element Ta is mainly distributed in the γ′ phase. Element Mg enters the γ matrix phase and segregates at the grain boundaries. The high-temperature alloy provided by the present invention has excellent comprehensive performance. The alloy has high creep resistance above 780℃, which enables the high-temperature alloy of the present invention to reach a maximum operating temperature of 780℃, making it suitable for even higher maximum operating temperatures.

[0023] d) In the preparation method of the present invention, air cooling can be used in the solution treatment and aging treatment steps to obtain nickel-based powder superalloys with high creep resistance. The process is simple and economical, environmentally friendly and widely applicable compared with commonly used cooling methods such as salt cooling or oil cooling.

[0024] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained from the written description. Attached Figure Description

[0025] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] Figure 1 The γ′ phase morphology characterization results of the heat-treated GNPM14 high-temperature alloy in the embodiments of the present invention are shown.

[0027] Figure 2 The results show the characterization of the relationship between the high-temperature alloy LM parameter P and stress σ in the embodiments of the present invention. Detailed Implementation

[0028] The preferred embodiments of the present invention are described in detail below. These embodiments are only used to illustrate the principles of the present invention and are not intended to limit the scope of the present invention.

[0029] This invention provides a high-temperature alloy, wherein the mass fraction of each element in the high-temperature alloy comprises: C 0.06%–0.07%, Co 17.0%–19.0%, Cr 9.0%–11.0%, Mo 2.3%–2.7%, W 3.4%–4.8%, Ta 2.9%–4.5%, Al 3.45%–3.8%, Ti 3.25%–3.6%, Nb 1.2%–1.8%, Hf 0.2%–0.4%, Zr 0.04%–0.06%, B 0.03%–0.05%, Mg 0.002%–0.010%, and the balance Ni.

[0030] Specifically, the mass fraction ratio of (C+Ti) / (Ti+Nb+Ta+Hf) is 0.30–0.50, the total mass fraction of Co, Cr, Mo, and W is 32.0%–37.0%, the total mass fraction of W and Ta is 7.0%–8.0%, the mass fraction ratio of Ta to W (Ta / W) is 0.6–1.3, the total mass fraction of Al, Ti, Nb, Ta, and Hf is 11.0%–14.0%, and the total mass fraction of Al and Ti is 6.8%–7.2%.

[0031] Specifically, the microstructure of the high-temperature alloy of the present invention includes a γ matrix phase and precipitated phases, with a uniform structure and dispersed precipitated phases. The precipitated phases mainly include γ′ phase, MC-type carbides, and M3B2-type borides. The γ′ phase is of the (Ni,Co)3(Al,Ti,Ta,Nb,W,Hf) type, and the MC-type carbides are of the (Ti,Ta,Nb,Hf)C type. Element Ta is mainly distributed in the γ′ phase, and element Mg enters the γ matrix phase and segregates at the grain boundaries.

[0032] Specifically, the content of the aforementioned γ′ phase is 57%–62% (mass fraction).

[0033] Specifically, 62% to 70% of Ta enters the γ′ phase.

[0034] Specifically, the complete dissolution temperature of the aforementioned γ′ phase is 1180℃~1210℃.

[0035] Specifically, considering that the effect of coarse grains on improving creep resistance cannot be ignored, the grain size of the above-mentioned high-temperature alloy is 4.5 to 5.0.

[0036] The elements in this invention will be described in detail below, and the content refers to the mass fraction of each element.

[0037] This invention strengthens the alloy by adding solid solution strengthening elements (Co, Cr, Mo, W), γ′ phase forming elements (Al, Ti, Nb, Ta, Hf), and grain boundary strengthening elements (B, Zr, Mg). By adding a high (W+Ta) content and an appropriate amount of Mg, combined with coarse grains, the alloy achieves excellent high-temperature creep resistance, thus obtaining a composition range with good comprehensive mechanical properties.

[0038] In the high-temperature alloy of this invention, element Mg enters the γ-matrix phase and segregates at the grain boundaries, strengthening them and thus improving creep resistance and endurance strength. Mg reacts with element S to form high-melting-point MgS, which purifies the grain boundaries and reduces the harmful effects of S. An appropriate amount of Mg can effectively disperse and refine coarse carbides at the grain boundaries; too low a Mg content has little effect, while too high a Mg content causes the grain boundary carbides to aggregate, easily forming cracks during creep and causing adverse effects. Therefore, in this invention, the Mg content is controlled at 0.002% to 0.010%.

[0039] Secondly, in this invention, by controlling the (C+Ti) / (Ti+Nb+Ta+Hf) content ratio to below 0.5, the precipitation of MC-type carbides at the original particle boundaries of the powder is eliminated, i.e., the original particle boundary structure (PPBS) is eliminated, so as to avoid the resulting degradation of mechanical properties; therefore, in this invention, the mass fraction ratio of (C+Ti) / (Ti+Nb+Ta+Hf) is controlled to be 0.30 to 0.50.

[0040] This invention reduces the tendency for TCP phase precipitation and improves the high-temperature microstructure stability of the alloy by coordinating and controlling the content of elements such as Co, Cr, Mo, and W, thereby enabling the alloy to have a higher maximum operating temperature. Therefore, the total mass fraction of Co, Cr, Mo, and W is controlled at 32.0% to 37.0% in this invention.

[0041] Due to factors such as crystal structure, atomic size, and self-diffusion coefficient, elements W and Ta can enter both the γ matrix and the γ′ phase, with Ta mostly entering the γ′ phase. Therefore, they simultaneously strengthen both the γ matrix and the γ′ phase, with Ta having a more significant effect on strengthening the γ′ phase. W and Ta contribute to improving the high-temperature creep resistance of the alloy, especially Ta, which has a more pronounced effect on improving high-temperature creep resistance. Ta causes element W to have a reverse distribution effect, meaning that as the amount of Ta added increases, more W enters the γ matrix phase. The higher the total amount of W and Ta, the better the high-temperature creep resistance and endurance performance. Only when the total mass fraction of W and Ta is above 7.0% can excellent creep resistance and endurance performance at 780℃ be obtained. Therefore, in this invention, the total mass fraction of W and Ta is controlled at 7.0%–8.0%, and the mass fraction ratio of Ta to W, Ta / W, is 0.6–1.3.

[0042] To further improve the creep resistance of the high-temperature alloy, the mass fraction of each element in the high-temperature alloy of the present invention may include: C 0.061%–0.066%, Co 17.6%–18.4%, Cr 9.5%–10.2%, Mo 2.4%–2.6%, W 3.4%–4.6%, Ta 2.9%–4.1%, Al 3.5%–3.75%, Ti 3.3%–3.55%, Nb 1.3%–1.6%, Hf 0.22%–0.38%, Zr 0.04%–0.055%, B 0.031%–0.05%, Mg 0.003%–0.008%, and the balance Ni.

[0043] Preferably, the mass fraction ratio of (C+Ti) / (Ti+Nb+Ta+Hf) is controlled to be 0.35 to 0.45.

[0044] Preferably, the total mass fraction of Co, Cr, Mo, and W is controlled to be 33.0% to 36.0%.

[0045] Preferably, the total mass fraction of W and Ta is controlled to be 7.3% to 8.0%.

[0046] Preferably, the mass fraction ratio of Ta to W, Ta / W, is controlled to be 0.6 to 1.15.

[0047] Preferably, the total mass fraction of Al, Ti, Nb, Ta, and Hf is controlled to be 11.5% to 13.5%.

[0048] Preferably, the total mass fraction of Al and Ti is controlled to be 6.85% to 7.15%.

[0049] This invention also provides a method for preparing a high-temperature alloy, comprising the following steps:

[0050] Step 1: Prepare the alloy using vacuum induction melting process according to the mass fraction ratio, and obtain alloy bars;

[0051] Step 2: The alloy rod is powdered, sieved, and electrostatically treated using the plasma rotating electrode method to obtain alloy powder with a diameter of 50μm to 150μm.

[0052] Step 3: Under vacuum conditions, the alloy powder is loaded into a low-carbon steel sleeve, degassed and sealed, and then hot isostatically pressed to obtain an ingot.

[0053] Step 4: Heat treat the ingot, including solution treatment and aging treatment, to obtain a high-temperature alloy.

[0054] Specifically, in step 2 above, the powder is cooled in a mixture of argon and helium gas during the powder preparation process. The cooling rate is extremely fast, resulting in micron-sized alloy powder with uniform alloy composition.

[0055] Specifically, in step 3 above, the process parameters for hot isostatic pressing are: temperature 1190℃~1210℃, pressure 120MPa~140MPa, and holding time 3h~6h.

[0056] Specifically, in step 4 above, the solution treatment process parameters are: 1190℃~1220℃ / 2h~6h / air cooling, and the aging treatment process parameters are: 790℃~820℃ / 4h~16h / air cooling.

[0057] In the preparation method of the present invention, the alloy composition is uniform because the micron-sized alloy powder of the high-temperature alloy is formed by cooling at a high cooling rate.

[0058] The high-temperature alloy of the present invention has a uniform microstructure and a dispersed distribution of precipitates, which eliminates macroscopic segregation and can further improve the degree of alloying, giving the alloy good high-temperature tensile strength, yield strength and high-temperature creep resistance.

[0059] Specifically, the mechanical properties of the above-mentioned high-temperature alloys are as follows:

[0060] Mechanical properties at room temperature: tensile strength of ≥1570MPa (e.g., 1579–1586MPa), yield strength of ≥1150MPa (e.g., 1150–1160MPa), elongation after fracture of ≥13.5% (e.g., 13.5%–16.5%), and reduction of area of ​​≥12% (e.g., 12.0%–15.0%).

[0061] Creep resistance at 780℃: Test conditions 780℃ / 550MPa: Plastic strain less than 0.18% after 50h, e.g., 0.13%–0.18%; Creep service life greater than 480h, e.g., 486–665h; Minimum creep rate 1.2 × 10⁻⁶. -8 s -1 For example, 9.2 × 10 -9 ~1.2×10 -8 s -1 The creep strength at 780℃ / 100h is greater than 680MPa.

[0062] In the preparation method of the present invention, air cooling can be used in the solution treatment and aging treatment steps to obtain a high-temperature alloy with high creep resistance that can be used at 780℃. The process is simple and economical, environmentally friendly and widely applicable compared with commonly used cooling methods such as salt cooling or oil cooling.

[0063] The high-temperature alloy of the present invention can reach a maximum operating temperature of 780°C and a creep strength of more than 680 MPa at 780°C / 100h, which can meet the stringent requirements of engines for material performance at high temperatures and can be used as a high-temperature material in temperature scenarios of 780°C.

[0064] The advantages of precise control of the composition and process parameters of the high-temperature alloy of the present invention will be demonstrated below with specific embodiments and comparative examples.

[0065] Example

[0066] This embodiment provides a high-temperature alloy. The composition and processing conditions of the high-temperature alloy in this embodiment are shown in Table 1 below. GNPM14 to GNPM16 are embodiments of the present invention. # and 2 # The sample with relatively poor results during the inventor's research process serves as a comparative example of this invention. FGH4098 is a commonly used high-temperature alloy and serves as a comparative example of this invention.

[0067] The specific preparation method of the above-mentioned high-temperature alloy is as follows:

[0068] (1) Prepare raw materials according to the chemical composition and mass fraction of the high-temperature alloy, and prepare alloy bars using a 25kg vacuum induction melting process;

[0069] (2) The alloy rods were prepared into high-temperature alloy powder by plasma rotating electrode method. The alloy powder was sieved and electrostatically treated to obtain alloy powder with a particle size of 50μm to 150μm.

[0070] (3) Under vacuum conditions, the alloy powder is loaded into a low-carbon steel sheath, degassed and sealed.

[0071] (4) The sealed sleeve is subjected to hot isostatic pressing to obtain an ingot;

[0072] (5) Heat treatment is performed on the formed ingot to obtain powder high-temperature alloy parts; heat treatment includes solution treatment and aging treatment.

[0073] Table 1. Composition and preparation process parameters of high-temperature alloy samples

[0074]

[0075]

[0076] The microstructure of the above alloys in the heat-treated state and after long-term aging was observed using a metallographic microscope to characterize the prepared GNPM14~GNPM16, 1 # and 2 # Microstructure of high-temperature alloys.

[0077] Taking GNPM14 high-temperature alloy as a typical example, its heat-treated γ′ phase morphology is as follows: Figure 1 As shown.

[0078] The microstructure of the high-temperature alloy provided by this invention mainly consists of a matrix γ phase, a γ′ phase, MC-type carbides, and M3B2-type borides. The γ′ phase is of the (Ni,Co)3(Al,Ti,Ta,Nb,W,Hf) type, and the MC-type carbides are of the (Ti,Ta,Nb,Hf)C type. The element Ta is mainly distributed in the γ′ phase, and the element Mg enters the γ matrix phase and segregates on the grain boundaries.

[0079] GNPM14~GNPM16, 1 # and 2 # The high-temperature alloy contains 58%–60% (mass fraction) of γ′ phase, with a complete dissolution temperature of 1190–1200℃ and a grain size of 4.5–5.0. Coarse grains are beneficial for improving creep resistance and service life.

[0080] Microstructural observation showed that no TCP phase precipitated after the high-temperature alloy was aged at 780℃ for 3000h, indicating that it has excellent high-temperature structural stability at 780℃.

[0081] GNPM14~GNPM16, 1 # and 2 # The room temperature mechanical properties and 780℃ creep resistance of the high-temperature alloy are listed in Tables 2 and 3, respectively. The relationship between the LMP parameter P and the stress σ is as follows: Figure 2 As shown.

[0082] Table 2 Room temperature mechanical properties of high-temperature alloys

[0083] Alloy Number <![CDATA[R m / MPa]]> <![CDATA[R p0.2 / MPa]]> A / ％ Z / ％ GNPM14 1586 1153 13.5 13.0 GNPM15 1579 1150 14.0 12.0 GNPM16 1582 1151 16.5 15.0 <![CDATA[1 # ]]> 1570 1142 17.0 18.5 <![CDATA[2 # ]]> 1568 1141 17.5 18.0 FGH4098 1587 1152 18.0 21.0

[0084] Table 3. Creep resistance of high-temperature alloys at 780℃

[0085] Alloy Number Test conditions 50h plastic strain / % <![CDATA[Minimum creep rate / s -1 > Durability / h GNPM14 780℃ / 550MPa 0.18 <![CDATA[9.4×10 -9 ]]> 582 GNPM15 780℃ / 550MPa 0.18 <![CDATA[1.2×10 -8 ]]> 486 GNPM16 780℃ / 550MPa 0.13 <![CDATA[9.2×10 -9 ]]> 665 <![CDATA[1 # ]]> 780℃ / 550MPa 0.25 <![CDATA[1.4×10 -8 ]]> 450 <![CDATA[2 # ]]> 780℃ / 550MPa 0.27 <![CDATA[1.6×10 -8 ]]> 420 FGH4098 780℃ / 550MPa 0.87 <![CDATA[4.7×10 -8 ]]> 240

[0086] From the data in Table 3 and Figure 2 As can be seen, compared with the existing FGH4098 alloy, the minimum creep rate of the alloy of the present invention at 780℃ is significantly reduced, while the creep rupture life and creep strength are also significantly improved. The creep rupture strength of the alloy of the present invention at 780℃ / 100h is greater than 680MPa. Therefore, the high-temperature alloy provided by the present invention exhibits excellent high-temperature creep resistance at 780℃.

[0087] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high temperature alloy, characterized by, The mass fraction of each element of the high-temperature alloy comprises: C 0.06% to 0.07%, Co 17.0% to 19.0%, Cr 9.0% to 11.0%, Mo 2.3% to 2.7%, W 3.52% to 4.8%, Ta 2.9% to 4.5%, Al 3.45% to 3.8%, Ti 3.25% to 3.6%, Nb 1.2% to 1.8%, Hf 0.2% to 0.4%, Zr 0.04% to 0.06%, B 0.03% to 0.05%, Mg 0.002% to 0.010%, and the balance of Ni; The total mass fraction of W and Ta is 7.0% to 8.0%; The mass fraction ratio of Ta to W is 0.6 to 1.3; The microstructure of the high-temperature alloy comprises a γ matrix phase and a precipitated phase, the structure is uniform, and the precipitated phase is dispersedly distributed; the precipitated phase mainly comprises a γ' phase, an MC type carbide and an M3B2 type boride; the composition of the γ' phase is (Ni, Co)3(Al, Ti, Ta, Nb, W, Hf) type, and the composition of the MC type carbide is (Ti, Ta, Nb, Hf)C type; element Ta is mainly distributed in the γ' phase; element Mg enters the γ matrix phase and is segregated on the grain boundary; The content of the γ' phase is 57% to 62%, 62% to 70% of Ta enters the γ' phase, and the grain size of the high-temperature alloy is 4.5 to 5.0 levels; Creep resistance of the superalloy at 780°C: test conditions 780°C / 550 MPa: plastic strain 0.18% or less for 50 h; endurance life 480 h or more; minimum creep rate 1.2 x 10 -8 s -1 The 780°C / 100 h endurance strength is greater than 680 MPa.

2. The superalloy of claim 1, wherein, The mass fraction ratio of (C+Ti) to (Ti+Nb+Ta+Hf) is 0.30 to 0.

50.

3. The superalloy of claim 1, wherein, The total mass fraction of Co, Cr, Mo and W is 32.0% to 37.0%.

4. The superalloy of claim 1, wherein, The total mass fraction of W and Ta is 7.3% to 8.0%.

5. The superalloy of claim 1, wherein, The mass fraction ratio of Ta to W is 0.6 to 1.

15.

6. The superalloy of claim 1, wherein, The total mass fraction of Al, Ti, Nb, Ta and Hf is 11.0% to 14.0%.

7. The superalloy of claim 1, wherein, The total mass fraction of Al and Ti is 6.8% to 7.2%.

8. A method of producing a high-temperature alloy, characterized by, A method for manufacturing the high-temperature alloy of any one of claims 1 to 7 comprises the following steps: Step 1, preparing an alloy by vacuum induction melting process according to the mass fraction, and obtaining an alloy bar; Step 2, powdering the alloy bar by plasma rotating electrode method, screening, and electrostatic treatment to obtain an alloy powder of 50 μm to 150 μm; Step 3, under vacuum condition, loading the alloy powder into a low-carbon steel jacket, degassing and sealing, and then performing hot isostatic pressing to obtain an ingot; Step 4, performing heat treatment on the ingot, the heat treatment comprising solid solution treatment and aging treatment, to obtain the high-temperature alloy with high creep resistance.

9. The production method according to claim 8, characterized by, In the step 4, the solid solution treatment process parameters are 1190°C to 1220°C / 2h to 6h / air cooling, and the aging treatment process parameters are 790°C to 820°C / 4h to 16h / air cooling.

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