Helm, Dietmar et al.Download PDFPatent Trials and Appeals BoardNov 12, 202014237929 - (D) (P.T.A.B. Nov. 12, 2020) Copy Citation UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 14/237,929 03/03/2014 Dietmar Helm 6570-P50118 5753 13897 7590 11/12/2020 Abel Schillinger, LLP 5929 Balcones Drive Suite 300 Austin, TX 78731 EXAMINER HEVEY, JOHN A ART UNIT PAPER NUMBER 1735 NOTIFICATION DATE DELIVERY MODE 11/12/2020 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): hmuensterer@abel-ip.com mail@Abel-IP.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte DIETMAR HELM, FALKO HEUTLING, ULRIKE HABEL, and WILFRIED SMARSLY Appeal 2019-005516 Application 14/237,929 Technology Center 1700 ____________ Before MICHAEL P. COLAIANNI, N. WHITNEY WILSON, and DONNA M. PRAISS, Administrative Patent Judges. COLAIANNI, Administrative Patent Judge. DECISION ON APPEAL Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the Examiner’s decision to reject claims 8, 11–14, 17–19, 21–25, and 28–35. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. 1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42. Appellant identifies MTU Aero Engines AG as the real party in interest. (Appeal Br. 3). Appeal 2019-005516 Application 14/237,929 2 Appellant’s invention is directed to a method of producing forged components of TiAl alloy, in particular components for gas turbines. (Spec. 1:8-9; Appeal Br. 21, Claims App.). Claim 8 is representative of the subject matter on appeal: 8. A method for producing a forged component of a TiAl alloy, wherein the method comprises forging the component and thereafter subjecting it to a two-stage heat treatment, and wherein (i) a first stage of the heat treatment comprises recrystallization annealing for 50 to 100 minutes at a temperature below a γ/α transition temperature, (ii) a second stage of the heat treatment comprises stabilization annealing in a temperature range of from 800°C to 950°C for 5 to 7 h, and (iii) a cooling rate during the first stage of the heat treatment is greater than or equal to 3°C/s in a temperature range of from 1300°C to 900°C to afford a finely lamellar micro structure of α2-Ti3Al and γ-TiAl in a corresponding α2 and γ phase. Appellant appeals the following rejections: 1. Claims 8, 11, 13, 14, 17–19, 22, and 28–33 are rejected under 35 U.S.C. § 103(a) as unpatentable over Droessler (Droessler et al., Microstructure and Tensile Ductility of a Ti-43A1-4Nb- 1Mo-0.1B Alloy, Mater. Research Society Symp. Proc., Vol. 1128, 121–126 (2009), hereinafter “Droessler”) in view of Clemens (Clemens, et al., Design of Novel ß-Solidifying TiAl Alloys with Adjustable ß/B2-Phase Fraction and Excellent Hot- Workability, Advanced Engineering Materials, Vol. 10, No. 8 (2008), hereinafter “Clemens”) and Park (Park et al., Microstructural Refinement and Mechanical Properties Improvement of Elemental Powder Metallurgy Processed Ti- Appeal 2019-005516 Application 14/237,929 3 46.6Al-1.4Mn-2Mo Alloy by Carbon Addition, Metallurgical and Materials Transactions A, Vol. 32A, 251–259 (2001), hereinafter “Park”). 2. Claim 21 is rejected under 35 U.S.C. § 103(a) as unpatentable over Droessler in view of Clemens, Park, Smarsly (Smarsly et al., US 2011/0189026 A1; pub. Aug. 4, 2011, hereinafter “Smarsly”), and Eberhardt (Eberhardt et al., US 6,161,285; iss. Dec. 19, 2000, hereinafter “Eberhardt”). 3. Claims 23–25, 34, and 35 are rejected under 35 U.S.C. § 103(a) as unpatentable over Droessler in view of Clemens, Park, and Kim (Kim et al., US 5,558,729; iss. Sept. 24, 1996, hereinafter “Kim”). 4. Claims 8, 11, 13, 14, 22, 23, 34, and 35 are rejected under 35 U.S.C. § 103(a) as unpatentable over Kim in view of Clemens. 5. Claim 21 is rejected under 35 U.S.C. § 103(a) as unpatentable over Kim in view of Clemens, Smarsly, and Eberhardt. FINDINGS OF FACT AND ANALYSIS Rejections (1) to (3) Appellant’s arguments focus on the subject matter of claim 8 and the group of claims 29–31 under rejection (1) and claim 23 under rejection (3). (Appeal Br. 6–15). With regard to claim 21, Appellant argues Smarsly and Eberhardt do not cure the argued deficiencies of Droessler, Clemens, and Park. (Appeal Br. 13). Accordingly, claim 21 will stand or fall with our analysis of the rejection of claim 8. Appellant does not separately argue any Appeal 2019-005516 Application 14/237,929 4 of claims 29–31. Therefore, we select claim 29 as representative of the arguments made with this claim grouping. 37 CFR § 41.37(c)(iv). The Examiner’s findings regarding the obviousness rejections (1) and (3) are located on pages 3–5 and 7–8 of the Final Action, respectively. The Examiner finds Droessler generally teaches the method recited in claim 8 for forming a TiAl alloy, except for “a cooling rate during the first stage of the heat treatment is greater than or equal to 3°C/s in a temperature range of from 1300°C to 900°C.” (Final Act. 3). The Examiner finds Droessler teaches the same two-step heat treatment method with temperatures and times that overlap those recited in claim 8. (Final Act. 3). The Examiner finds Clemens teaches forming a TiAl alloy using a two stage heat treatment with similar temperatures and times as recited in claim 8 and in Droessler. (Final Act. 3). The Examiner finds Clemens teaches air cooling after the first heat treatment using a high cooling rate in order to obtain a very fine lamellar spacing. (Final Act. 3). The Examiner finds Park teaches the effect of cooling rates on the grain size of lamellar α2 and γ phase of a TiAl alloy material. (Final Act. 4). The Examiner finds Park teaches using a cooling rate of 200°C/min (i.e., 3.33°C/s). (Final Act. 4). The Examiner finds Park teaches air cooling occurs at a higher cooling rate and results in smaller lamellar phase grain size. (Final Act. 4). Based upon the similarity of the processes in Droessler, Clemens, and Park, the Examiner concludes that it would have been obvious to modify the method of Droessler to perform a step of rapid air cooling at a rate above 3.3°C/s after a first heat treatment in order to obtain a desired microstructure such as lamellar α2 and γ phases of TiAl. (Final Act. 4). The Examiner Appeal 2019-005516 Application 14/237,929 5 finds that the selection of the temperature and time within the overlapping ranges would have been obvious. (Final Act. 4). Appellant argues that neither Droessler nor Clemens discloses any specifics regarding the cooling step that follows the first heat treatment such that there would have been no reason other than hindsight to use Park’s cooling rate in Droessler’s method. (Appeal Br. 7–8, 11). Appellant argues Droessler’s silence on the time or cooling rate used during the air cooling step evinces that the cooling conditions are of no importance for the microstructure or properties of Droessler’s final product. (Appeal Br. 10). Appellant argues air cooling is not associated with a single cooling rate but, rather, is dependent on velocity of the cooling air. (Appeal Br. 11). Appellant contends that Park’s alloy compositionally differs from Droessler’s alloy in that Park’s alloy contains more Al, no Nb, no B, more Mo, and Mn, which is not present in Droessler’s alloy. (Appeal Br. 9). Appellant argues that because there is a difference in alloy compositions, a person of ordinary skill in the art would not have expected that a cooling rate of 3.3°C/s in Park’s alloy would have the same effect in the alloy investigated by Droessler. (Id.). Appellant argues the Examiner has not shown that the effect of the cooling rate on microstructure of the alloy is independent of the alloy composition. (Id.). We have fully considered the Examiner’s findings and conclusions and Appellant’s arguments. We find that the preponderance of the evidence favors the Examiner’s obviousness conclusion. In the present case, the Examiner acknowledges that there may be “some compositional differences” between the alloys of Droessler, Clemens, and Park, but the Examiner finds that all three references teach methods of making TiAl-based alloys Appeal 2019-005516 Application 14/237,929 6 comprising lamellar α2 and γ phases. (Ans. 6). The Examiner finds that Droessler and Clemens teach two heat treatment steps followed by air cooling after the first step. (Ans. 6). The Examiner finds that Park teaches a first heat treatment step followed by cooling and the effect of cooling rates on microstructural features of the alloy. (Ans. 6). The Examiner finds that because TiAl alloys are processed in all three references, a person of ordinary skill in the art would have recognized the applicability of parameters for an air cooling step, such as cooling rate, for one TiAl-based alloy to another TiAl-based alloy. (Ans. 6). We agree. Appellant does not dispute that Droessler, Clemens, and Park teach an air cooling step after a first heat treatment of a TiAl-based alloy. (See generally Appeal Br.). The Examiner relies on Parks to teach the particular air cooling rate recited in claim 8 (i.e., greater than or equal to 3 °C/s). (Final Act. 4). The Examiner finds that Park teaches air cooling takes place at a higher cooling rate and results in smaller lamellar phase grain size. (Final Act. 4). Appellant does not particularly address this finding other than to argue that air cooling does not have a particular cooling rate. (Appeal Br. 11). Park experiments with three cooling rates: air cooling, 200 °C/min (i.e., 3.3 °C/s) and furnace cooling. (Park 253). Park determines from the experiment that grain size of the TiAl-based alloy increased with slow cooling regardless of the presence of carbon in the alloy composition from 70, 100 and 150 μm, which correspond to air cooling, 200°C/min and furnace cooling grain sizes, respectively. (Park 253). Based on Park’s teachings, the cooling method that produces the smallest grain size would appear to be the one with the greatest cooling rate. In this case, Park’s air cooling would have a higher cooling rate than 200 °C/min because air Appeal 2019-005516 Application 14/237,929 7 cooling yielded the smallest grain size (i.e., 70 μm) of the three cooling methods tested. Droessler teaches the grain size of the TiAl-based alloy after air cooling following the first heat treatment step is about 20 μm. (Droessler 123). Droessler’s grain size (20 μm) is smaller than Park’s grain size (70 μm) for the air cooled sample. This smaller grain size would have suggested that Droessler’s air cooling rate is greater than Park’s air cooling rate, which is faster than 3.3 °C/s. In light of Park’s teachings regarding grain size and cooling rate, the Examiner properly determines that the combined teachings of Droessler, Clemens and Park would have suggested using a cooling rate within the range recited in claim 8 in Droessler’s method. Appellant’s arguments about the differences in composition are not persuasive because the Examiner has shown that each reference has a similar composition based on titanium and aluminum. (Final Act. 3–4; Ans. 6). The Examiner finds that each of the references forms lamellar α2 and γ phase TiAl alloy. (Ans. 6). In other words, despite the difference in the presence of C, Mo, Nb, W, or other elements, the Examiner finds that the microstructure achieved is similar. All three references use a cooling step as part of the process to form the microstructure. (Droessler 122 (Table 1); Clemens 712; Park 253). Contrary to Appellant’s argument, a person of ordinary skill in the art would have had a reasonable expectation that using an air cooling method, which the art teaches has a high cooling rate, would have yielded a TiAl-based alloy having a finely lamellar microstructure as recited in claim 8. Appellant’s argument that Park’s and Clemens’ hot extrusion methods of forming the alloy are different than Droesseler’s forging process is not Appeal 2019-005516 Application 14/237,929 8 persuasive. (Appeal Br. 10). Clemens teaches forging a TiAl alloy and then subjecting the forged alloy to a two-step heat treatment. (Clemens 712). Park teaches a hot extruded alloy that is subject to a heat treating and cooling step. (Park 251). The Examiner finds and Appellant does not dispute that “the method of forming the material prior to the first heat treatment does not impact the effect of the cooling step nor the final microstructure of the alloy.” (Ans. 6; generally Reply Br.). Appellant’s argument does not establish reversible error with the Examiner’s findings and conclusions based thereon. With respect to dependent claim 292, Appellant argues that Droessler in view of Clemens and Park do not teach a method comprising substantially the same method of making the alloy as discussed with respect to claim 8 (Appeal Br. 12). The Examiner finds the particular proportions of β, α, and γ phases in the TiAl would have been expected to be similar because the prior art teaches similar TiAl alloys with minor amounts of other elements that differ and the TiAl alloys are heat treated and cooled using similar methods to those recited in claim 8 as found by the Examiner. (Final Act. 5). The Examiner further determines that it would have been obvious in light of Droesseler’s, Clemen’s and Park’s teachings to select optimum working conditions to obtain desired properties and microstructure with a reasonable expectation of success. (Final Act. 5). Appellant does not respond to the Examiner’s rationale based on optimizing the methods to obtain the desired 2 In the event of further prosecution, the dependency of claims 17, 18, and 28-33 must be corrected. All of these claims include cancelled claim 16 in their respective chain of dependency. Claim 16 was cancelled in an amendment filed May 4, 2018 (Advisory Act. 2). Appeal 2019-005516 Application 14/237,929 9 properties and microstructure (Appeal Br. 12–13) and, therefore does not demonstrate reversible error in it. . Regarding § 103 rejection (3) of independent claim 23 over Droessler in view of Clemens, Park, and Kim, Appellant argues that Kim does not cure the deficiencies argued in Droessler, Clemens, and Park. (Appeal Br. 14). We disagree for the reasons discussed above in the context of rejection (1) and because we find no deficiencies in the Examiner’s combination of Droessler, Clemens, and Park. The Examiner finds Droessler, Clemens, and Park would have suggested an accurate heating method in order to obtain precise results and avoid unwanted temperature variations, in order to obtain desired microstructure and properties. (Final Act. 7). The Examiner finds Droessler teaches a first heat treatment temperature below the α transition temperature, but does not specify that the transition temperature is 10°C below the α transition temperature. (Final Act. 7–8). The Examiner finds Kim teaches selecting a heating temperature between 1 to 20°C below the α transition temperature in order to obtain a fully lamellar microstructure. (Final Act. 8). The Examiner concludes it would have been obvious to modify the method of Droessler in view of Clemens and Park to select a first heat treatment temperature of from 1 to 20°C below the α transition temperature as taught by Kim in order to form a fully lamellar microstructure. (Final Act. 8). Appellant argues that Kim’s alloys differ significantly from the alloy of Droessler and Clemens because Kim’s alloys contains more aluminum, tungsten, but no molybdenum, and boron. (Appeal Br. 14). Appellant contends that Kim’s alloys include chromium and niobium which are not present in Droessler’s alloys. (Appeal Br. 15). Appellant contends that Appeal 2019-005516 Application 14/237,929 10 because of these significant alloy compositional differences, a person of ordinary skill in the art would not have combined the teachings of Kim and Droessler. (Appeal Br. 16). As with rejection (1) of claim 8, Appellant’s arguments about the differences in composition are not persuasive because the Examiner has shown that each reference has a similar alloy composition based on a titanium and aluminum. (Final Act. 3–4, 7–8; Ans. 6, 8). The Examiner finds that each of the references forms lamellar α2 and γ phase TiAl alloy. (Ans. 6, 8). In other words, despite the difference in the presence of C, Mo, Nb, W, or other elements, the Examiner finds that microstructure achieved is similar. All three references use a cooling step as part of the process to form the microstructure. (Droessler 122 (Table 1); Clemens 712; Park 253; Kim, col. 4, ll. 25–42). Contrary to Appellant’s argument, one of ordinary skill in the art would have had a reasonable expectation that using an air cooling method, which the art teaches has a high cooling rate, would have yielded a TiAl-based alloy having a finely lamellar microstructure as recited in claim 23. Based on this record, we affirm the Examiner’s § 103 rejections of claims 8, 11, 13, 14, 17–19, 21–25, and 28–35 over the combined teachings of Droessler, Clemens, Park, and Kim. Rejections (4) and (5) Appellant’s arguments focus on the subject matter common to claims 8 and 23. (Appeal Br. 16–19). We select claim 8 as representative of the argued group. 37 CFR § 41.37(c)(iv). Regarding rejection (5) of claim 21, Appellant relies on arguments made regarding rejection (4). (Appeal Br. Appeal 2019-005516 Application 14/237,929 11 19). The rejection of claim 21 will stand or fall with our analysis of the rejection of claim 8. The Examiner’s findings and conclusions regarding Kim and Clemens are located on pages 8 to 10 of the Final Office Action. The Examiner finds that Kim teaches that the a method of making a TiAl alloy that involves forging the alloy and using a two-step heat treatment process with a cooling step between the two heating steps. (Final Act. 8). The Examiner finds that the time and temperatures used for the two heat treatments in Kim overlap with the temperatures and times recited in claim 8. (Final Act. 8). The Examiner finds that Kim teaches an air cooling rate of approximately 16.7°C/sec (i.e., 1000°C/min). (Final Act. 8). The Examiner finds that Clemens teaches a two-step heat treatment process for forged TiAl alloy using high cooling rate between heat treatment steps to obtain very fine lamellar spacing. (Final Act. 9). The Examiner concludes that it would have been obvious to modify Kim’s method to use rapid air cooling rates up to 16.7°C/s in order to obtain a microstructure with very fine lamellar spacing as taught by Clemens. (Final Act. 9). Appellant argues that the presently recited cooling rate in claim 8, 3°C/s, is more than 30 times greater than the minimum cooling rate recited in Kim (i.e., 5°C/min or 0.083 °C/s). (Appeal Br. 16). Appellant contends that Clemens does not specify what constitutes a “high cooling rate.” (Appeal Br. 16). Appellant argues that Kim teaches that air cooling rates can vary over an extremely broad range (i.e., 5 to 1000°C/min). (Appeal Br. 16). Appellant contends that Kim’s disclosures of times and temperatures for the heating steps are too broad and lead to a virtually infinite number potential embodiments in Kim. (Appeal Br. 17). Appellant contends that Appeal 2019-005516 Application 14/237,929 12 the Examiner has not explained why a person of ordinary skill in the art would have select the claimed times and temperatures for the first and second heating steps and the cooling rates. (Appeal Br. 17). Appellant argues that Kim has not identified the time and temperatures to be result- effective variables. (Appeal Br. 17). Appellant argues that the Examiner engaged in impermissible hindsight. (Appeal Br. 17). Appellant argues that Kim’s and Clemen’s alloys differ significantly in that Kim’s alloy contains the following relative to Clemen’s alloy: more aluminum, tungsten, no Mo or B. (Appeal Br. 18). Contrary to Appellant’s argument, the Examiner’s rejection is based upon overlap in the time and temperature treatment of the two heat treatment steps and the cooling rate of Kim with those recited in claim 8. A prima facie case of obviousness typically exists when the ranges of a claim overlap with ranges disclosed in the prior art. In re Peterson, 315 F.3d 1325, 1329 (Fed. Cir. 2003). Appellant does not dispute that the claimed ranges overlap. (Appeal Br. 16–18). In this case the overlapping ranges create a prima facie case of obviousness at which time Appellant may submit evidence of criticality or unexpected results in using the particularly claimed time and temperature ranges. Peterson, 315 F.3d at 1330. The Examiner finds Appellant has not provided any evidence establishing criticality in the claimed cooling rate range. (Ans. 9). We find that Appellant also does not provide any evidence of criticality in the time or temperatures used by Appellant. The prior art’s teaching of overlapping ranges would have rendered obvious the claimed subject matter. Appellant’s argument about the ranges being too broad is not persuasive. Kim’s disclosure of a multitude of effective times, temperatures Appeal 2019-005516 Application 14/237,929 13 and cooling rates does not render any one combination of them less obvious. Merck v. Biocraft, 874 F.2d 804, 807 (Fed. Cir. 1989). Kim discloses that annealing at a temperature about 20°C below the transition temperature yields a fully lamellar TiAl alloy for a period of time from 0.25 to 15 hours depending on the desired microstructure, alloy selected, annealing temperatures selected, material section size and grain size desired. (Kim, col. 4, ll. 28–36). The cooling schemes and rates in Kim depend mainly on microstructure type and stability. (Kim, col. 4, ll. 36–38). The second heating step involves temperatures from 700 to 1050°C for 4 to 150 hours (Kim, col. 4, ll. 39–41). Kim’s teaching would teach a person of ordinary skill in the art to tailor the time, temperature and cooling rate within the claimed ranges to achieve the desired lamellar microstructure. Contrary to Appellant’s arguments, the Examiner is not generally relying on a result-effective variable analysis to conclude obviousness but, rather, the fact that Kim’s time, temperature and cooling rate ranges overlap with those recited in claim 8. (Ans. 9–10). The Examiner does find that Kim’s cooling rate is a result-effective variable that is critical for achieving the desired microstructures and mechanical properties. (Ans. 10). Kim’s teaching at column 5, lines 10–12 supports the Examiner’s finding. Moreover, Appellant does not specifically dispute that Kim’s cooling rate is a result effective variable. (Reply Br. generally). Appellant’s arguments regarding the difference in alloy composition are not persuasive for the same reasons discussed above with respect to Kim and Clemens in rejections (1) and (3). We add the difference in the amounts of interstitial (e.g., O and C) and substitutional (e.g., Cr, Mn, Ta, and W) alloying elements are known to decrease the transus temperature. (Kim, Appeal 2019-005516 Application 14/237,929 14 col. 2, ll. 34–41). Kim further teaches that transus temperature can be determined relatively routinely by standard isothermal treatments and metallography. (Kim, col. 2, ll. 38–40). Clemens teaches that Nb, Ta, Mo, and other elements stabilize the β-phase of the TiAl alloy and improve hot- workability of the alloy. (Clemens 707, 711). In other words, the prior art teaches the effect the alloying elements have on the alloy microstructure and it would have been within the skill level of the ordinarily skilled artisan to determine elemental amounts and alloy heat treatments/cooling rates to arrive at the process of claim 8. On this record, we affirm the Examiner’s 35 U.S.C. § 103 rejections (4) and (5) over the combined teachings of Kim, Clemens, Smarsly, and Eberhardt. CONCLUSION In summary: Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 8, 11, 13, 14, 17–19, 22, 28–33 103(a) Droessler, Clemens, Park 8, 11, 13, 14, 17–19, 22, 28–33 21 103(a) Droessler, Clemens, Park, Smarsly, Eberhardt 21 23–25, 34, 35 103(a) Droessler, Clemens, Park, Kim 23–25, 34, 35 8, 11, 13, 14, 22, 23, 34, 35 103(a) Kim, Clemens 8, 11, 13, 14, 22, 23, 34, 35 21 103(a) Kim, Clemens, Smarsly, Eberhardt 21 Overall Outcome 8, 11–14, 17–19, 21– Appeal 2019-005516 Application 14/237,929 15 Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 25, and 28– 35 No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R. § 1.136(a)(1)(iv). AFFIRMED Copy with citationCopy as parenthetical citation