Ex Parte Huang et al

Patent Trial and Appeal BoardOct 24, 2012

11889917 (P.T.A.B. Oct. 24, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE ____________________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________________ Ex parte AIJUN HUANG, MICHAEL LORETTO, XINHUA WU, and DAWEI HU ____________________ Appeal 2011-005830 Application 11/889,917 Technology Center 1700 ____________________ Before CHUNG K. PAK, CATHERINE Q. TIMM, and MARK NAGUMO, Administrative Patent Judges. TIMM, Administrative Patent Judge. DECISION ON APPEAL STATEMENT OF CASE Appellants appeal under 35 U.S.C. § 134 from the Examiner’s decision to reject claims 1-12. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM. Appellants’ invention relates to a process of subjecting a titanium aluminide alloy to a temperature cycle that produces a massively transformed gamma microstructure (Spec. 1:9-25; Spec. 6:18-25). As conveyed by the Specification, the particular temperature cycle used to Appeal 2011-005830 Application 11/889,917 2 obtain the massive transformation is taught by EP1378582A1 (Compare Spec. 1:9-25 with Spec. 3:6-12). Appellants’ improvement involves adding up to 0.5 at% of oxygen scouring means (e.g., yttrium) to the TiAl alloy (Spec. 2:28-32). Claim 1 is illustrative of the invention on appeal: 1. A method of enhancing massive transformation of a titanium aluminide alloy having a single alpha phase field, said method comprising: incorporating up to 0.5 at% of oxygen scouring means into the alloy which inhibits diffusion of oxygen within the alpha phase field to the grain boundary as the alloy is subjected to a temperature cycle which produces a massively transformed gamma microstructure. (Claims App.) The Examiner rejects claims 1-3, 5, and 8 under 35 U.S.C. § 102(b) as anticipated by Wu1, and claims 1-12 under 35 U.S.C. § 103(a) as obvious over Hu2 in view of Wu. OPINION A. ANTICIPATION BY WU All of the claims require forming a massively transformed gamma microstructure (see Claim 1). The Examiner finds that Wu teaches subjecting a TiAl alloy to a temperature cycle to produce a massively transformed gamma microstructure (Ans. 4, citing Wu, Abstract and Experimental section). Further, the Examiner finds that “since Wu teaches an identical process as 1 Wu et al., Influence of Y-addition on the oxidation behavior of Al-rich γ- TiAl alloys, Intermetallics 12(2004) 519-532. 2 Hu, US 2004/0003877 A1, pub. Jan 8, 2004. Appeal 2011-005830 Application 11/889,917 3 claimed, one skilled in the art would have envisaged that the process of Wu would have produced a massively transformed product as claimed.” (Ans. 6.) Wu’s Abstract states that Wu’s paper is directed to the study of the influence of yttrium on Al-rich γ-TiAl alloys containing 0.1-1.0 at% Y with equiaxial gamma microstructure, and explains Wu’s results (Abstract). Wu’s “Experimental procedure” section discloses the method of forming Y-free TiAl alloy and 0.1-1.0 at% Y containing TiAl alloy ingots to be tested. Forming the ingots involved annealing the ingots at 1200 °C for 72 h in an argon atmosphere to keep their compositional uniformity and stabilize the microstructure, and applying heat treatment cycles consisting of a solution treatment at 1400 °C for 1 h followed by air cooling (Wu, Experimental Procedure section at p. 520, ¶ 1). Wu states that “[m]etallographic examinations and X-ray diffractometry (XRD) revealed that microstructures consisted predominantly of equiaxial TiAl grains as shown in Figs. 1 and 2.” (Id.) Appellants contend that Wu’s figures illustrate non-massive microstructures, and massively transforming TiAl alloys requires rapid quenching whereas Wu discloses a slower air cooling (Br. 4). Appellants’ Specification discloses that the cooling rate affects the massive transformation of the gamma titanium aluminide (Spec 2:7-8). Cool too fast and the microstructure retains its alpha phase (Spec. 2:8-10). Cool too slow and the alloy will precipitate gamma grains (Spec. 2:10-11) The Examiner states that the process is identical without addressing Appellant’s argument concerning the cooling rate. The evidence as a whole indicates that cooling rate affects the conversion of the microstructure. Appeal 2011-005830 Application 11/889,917 4 Therefore, it was necessary for the Examiner to point out why it would have been reasonable to conclude that a massively transformed gamma microstructure would have necessarily resulted when performing the procedure of Wu. This the Examiner did not do. Moreover, the Examiner has not provided the level of evidence necessary to support the finding that one skilled in the art would have at once envisaged that the process of Wu would have produced a massively transformed product as claimed. Such a finding requires evidence of what those of ordinary skill in the art would have understood with regard to the microstructures described by Wu. We do not sustain the anticipation rejection. B. OBVIOUSNESS OVER HU AND WU With respect to the rejection of claims 1-12 as obvious over Hu in view of Wu, Appellants separately argue claims 3 and 9. We select claim 1 as representative for the claims not separately argued. 1. Claim 1 There is no dispute that Hu describes a method of subjecting a TiAl alloy to temperature cycling to obtain a massively transformed gamma microstructure (Compare Ans. 4-5 with Br. 5-7 and Reply Br. 2-4; see also Hu, Fig. 1, ¶¶ [0007-13]). The Examiner acknowledges that Hu does not teach incorporating oxygen scouring means, but that Wu teaches incorporating yttrium (an oxygen scouring means) in an amount of 0.1 at% into a TiAl alloy (Ans. 5). The Examiner concludes that it would have been obvious to one of ordinary skill in the art to incorporate yttrium, as taught by Wu, into the alloy of Hu since Wu teaches the addition of yttrium would improve the oxidation resistance of the alloy (id.). Appeal 2011-005830 Application 11/889,917 5 Appellants contend that Wu teaches using air cooling to provide a non-massive microstructure, which is a direction away from the claimed method and Wu cannot be used in combination with references teaching the opposite, i.e., to produce a massive microstructure (Hu) (Br. 5). Therefore, according to Appellants, Hu cannot be combined with Wu (id.). Appellants also contend that there is no motivation to incorporate yttrium into the method taught by Wu and that, even if Hu were combined with Wu, the claimed method would not have been obvious over the combination (Br. 5- 7). Appellants’ arguments give rise to the following issues: a. Have Appellants established that Hu “teaches away,” as that terminology is used in the context of obviousness, such that those of ordinary skill in the art would have been discouraged from incorporating yttrium into the TiAl alloy of Hu? b. Have Appellants identified a reversible error in the Examiner’s finding of a reason to incorporate concentrations of yttrium within the claimed range into the TiAl alloy of Hu to form a massively transformed gamma microstructure? We answer both questions in the negative based upon a weighing of the facts under the preponderance of the evidence standard and application of the applicable law. The following facts are relevant. Hu teaches a method of heat treating TiAl alloy that produces a massively transformed gamma microstructure (Hu, ¶¶ [0007-13]). Wu teaches that adding a small amount of yttrium (0.1 and 0.3 at%) to TiAl-based alloys improves the oxidation resistance of the alloy (Wu, Abstract). Wu states that oxidation rates, structures of scale, and scale Appeal 2011-005830 Application 11/889,917 6 spallation resistance were closely related to the concentration of yttrium in the TiAl alloys tested (Wu, Abstract; see also § 5 Conclusions). When forming the TiAl alloys to be tested, Wu subjected ingots of the TiAl alloys to heat treatment cycles consisting of solution treatment at 1400 °C for 1 h followed by air cooling, but Wu does not state that the heat treatment forms massively transformed gamma microstructure (Wu, Experimental procedure, ¶ 1). Appellants state that Wu clearly teaches using air cooling to provide a non-massive microstructure, however, Appellants do not point to any language in Wu indicating that Wu teaches a non-massively transformed gamma microstructure (Br. 5). Nor do Appellants explain the basis of their interpretation of the figures in Wu as showing non-massively transformed microstructures. Wu appears to be merely silent with respect to the presence of a massively transformed gamma microstructure (Wu, generally). “What the prior art teaches and whether it teaches toward or away from the claimed invention . . . is a determination of fact.” Para-Ordnance Mfg., Inc. v. SGS Importers Int’l., Inc., 73 F.3d 1085, 1088 (Fed. Cir. 1995) (citing In re Bell, 991 F.2d 781, 784 (Fed. Cir. 1993)). When there is nothing within the reference teaching that the claimed element should not, or cannot, be used, and further cited prior art teaches the propriety of employing the missing element, the teachings of both references must be weighed together. Para-Ordninace, 73 F.3d at 1090. Hu discloses the propriety of employing a temperature cycle to produce a massively transformed gamma microstructure in TiAl alloys. Appellants have not pointed to any disclosure within Wu teaching that TiAl alloys should not be so temperature cycled to form a massively transformed Appeal 2011-005830 Application 11/889,917 7 gamma microstructure or that one of ordinary skill in the art would have been lead to believe from Wu that adding yttrium in the small amounts disclosed by Wu would have not been thought to provide TiAl alloys having such microstructure with the oxygen resistance properties disclosed by Wu. Wu does not criticize, discredit, or otherwise discourage the path of the proposed combination. Therefore, Appellants have not established that Hu teaches away from the claimed method. With regard to the second issue, we do not agree with Appellants that the Examiner’s finding of a suggestion to combine the references is unsupported by the evidence. As pointed out by Appellants, Wu incorporates oxygen for a somewhat different reason than Appellants, i.e., to obtain oxygen resistance rather than to scour oxygen during temperature cycling. That fact, however, does not translate to a conclusion of non-obviousness. The problem faced by an applicant is a relevant factor to take into consideration in an obviousness determination. However, it is error to look “only to the problem the patentee [or applicant] was trying to solve.” KSR Int. Co. v. Teleflex Inc., 550 U.S. 398, 420 (2007). There may be other reasons within the prior art for making the combination. “As long as some motivation or suggestion to combine the references is provided by the prior art taken as a whole, the law does not require that the references be combined for the reasons contemplated by the inventor.” In re Beattie, 974 F.2d 1309, 1312 (Fed. Cir. 1992). In the present case, Wu indicates that small amounts of yttrium will increase the oxidation resistance of TiAl alloys. Hu teaches a TiAl alloy. Under the circumstances, there is a reasonable expectation that small Appeal 2011-005830 Application 11/889,917 8 amounts of yttrium will provide the properties of oxidation resistance discussed by Wu when used in the TiAl alloy treated in accordance with the method of Hu. Appellants discuss an unexpected advantage arising from the combination (Br. 6-7). According to Appellants, adding yttrium allows the quench to be performed at a slower rate (Br. 6). However, the fact that there is an additional advantage does not negate the fact that there is a reason within the prior art to add yttrium to the alloy of Hu. Appellants do not appear to be relying upon any showing of unexpected results. Suffice it to say that Appellants have not presented any objective data showing an unexpected result commensurate in scope with claim 1. Appellants have not identified a reversible error in the Examiner’s finding of a reason to incorporate concentrations of yttrium within the claimed range into the TiAl alloy of Hu to form a massively transformed gamma microstructure. 2. Claim 3 Claim 3 recites that the temperature cycle of claim 1 comprises steps of heating, maintaining, and cooling (Claim 3 as reproduced in Claims App). There is no dispute that the temperature cycle steps are taught by Hu (Compare Br. 5-7 with Ans. 4-5; see also Hu, ¶¶ [0007-13]). Appellants merely point out what the Examiner acknowledges the references fail to teach (Br. 7) without addressing the Examiner’s specific findings and conclusions (Ans. 4-5). We cannot say that Appellants have identified a reversible error in the Examiner’s rejection of claim 3. 3. Claim 9 Appeal 2011-005830 Application 11/889,917 9 Claim 9 further requires that the cooling step of claim 3 comprise cooling at a rate of 4 °C.S-1 to 150 °C.S-1. Appellants state that prior to their invention the quenching step had to be conducted rapidly to maintain the massive transformation, but that surprisingly the addition of the claimed oxygen scavenging means allows the quenching rate to be significantly reduced (Br. 8, citing Spec. 7:3-6 and 8:7- 18). Appellants contend that the claimed cooling range, having a lower limit of only 4 °C.S-1 is obtainable using the claimed oxygen scavenging means, and alloys such as those disclosed in Hu cannot be cooled at this slow rate to product a massive transformation (Br. 8). The claimed cooling rate encompasses cooling rates as high as 150 °C.S-1. Hu discloses air cooling or oil cooling at a rate sufficient to induce massively transformed gamma microstructure (Hu, ¶¶ [0019] and [0040]). A preponderance of the evidence supports a determination that the cooling rate one of ordinary skill in the art would have applied to the TiAl alloy would have been within the very broad range of claim 9, which encompasses very high cooling rates of 150 °C.S-1. Appellants have not convinced us of a reversible error in the Examiner’s rejection. CONCLUSION We do not sustain the Examiner’s rejection of claims 1-3, 5, and 8 under 35 U.S.C. § 102(b) as anticipated by Wu. However, we sustain the Examiner’s rejection of claims 1-12 under 35 U.S.C. § 103(a) as obvious over Hu in view of Wu. Appeal 2011-005830 Application 11/889,917 10 DECISION The Examiner’s decision is affirmed. TIME PERIOD FOR RESPONSE No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a)(1). AFFIRMED kmm