i v covsermn e £ 3 4456 0549331 0 joNAL LABORATORY operated by UNION CARBIDE CORPORATION w for the U.S. ATOMIC ENERGY COMMISSION ORNL- TM- 1353 STUDIES OF THE CARBON DISTRIBUTION IN HASTELLOY N H. E. McCoy CENTRAL RESEARCH LIBRARY DOCUMENT COLLECTION o LIBRARY LOAN COPY o DO NOT TRANSFER TO ANOTHER PERSON ‘.fll if you wish someone else to see this document, send in name with document e and the library will arrange a loan. 2 pd = i - LRI S B S "'. ~ T a . 2 - NP L S e W e "2 = - = ¥ NOTICE This document contains information of a preliminary nature and was prepared primarily for internal use at the Oak Ridge National Laboratery. It is subject to revision or correction and therefore does not represent a final report. ¥ 3% . jp ———— LEGAL MNOTICE — P This report was prepared os on cccount of Government sponsored work. Meither the United States, nor the Cemmission, nor any person acting on behalf of the Commission: A, Mokes aony warronty or representotion, expressed or implied, with respect to the accuracy, [ completeness, or usefulness of the information contained in this repart, or that the use of any informotion, opporatus, method, or process disclosed in this report moy not infringe privately owned rights; or B. Assumes ony liabilities with respact to ths use of, or for damages resulting frem the use of ony information, apparatus, method, or process disclosed in this report. As used in the obove, “‘person ceting on behalf of the Commission' includes any employee or contracter of the Commission, or employee of such contractor, to the extent that such employee or controctor of the Commission, or employee of such controctor prepores, disseminates, or provides access to, ony informotion pursuent to his employment or controct with the Commission, or his amployment with such contracter. - ORNL-TM~1353 Contract No. W-7405-eng-26 METALS AND CERAMICS DIVISION STUDIES OF THE CARBON DISTRIBUTION IN HASTELLOY N H. E. McCoy FEBRUARY 1966 OAK RIDGE NATIONAL LABORATORY Oak Ridge, Tennessee operated by UNION CARBIDE CORPORATION for the U.5, ATCMIC ENERGY COMMISSION OAK RIDGE NATIONAL LABORATORY LIBRARIES 3 44565 0549331 O STUDIES OF THE CARBON DISTRIBUTION IN HASTELLOY N H. E. McCoy ABSTRACT A small heat of Hastelloy N was prepared in which a portion of the carbon atoms were tagged as carbon-14. The response of this alloy to heat treat- ment was studied in an effort to determine whether the changes in mechanical properties could be correlated with the observed changes in the carbon distribution. Although marked segregation resulted, the changes in mechanical properties did not appear to be related. A second objective of this study was to determine whether the relatively large precipitates in this alloy were carbides. These precipitates, in both their stringer (low-temperature) and lamellar (high-temperature) forms, were found to be as low or lower in carbon than the matrix. It is hypothesized that the other alloying elements reduce the solubility of molybdenum in nickel so that the precipitates are basically nickel- molybdenum intermetallic compounds. INTRODUCTION Previous studies® of Hastelloy N have shown that the fracture ductility of this alloy at elevated temperatures is very sensitive to the thermal history of the alloy. Although numerous metallographic changes have been observed, it has not been possible to correlate these changes with the changes in the properties. Most of the metallographic changes involve the fairly coarse precipitate particles (0.1 to 1 mil in diameter) which are normally present as stringers. As the alloy is taken to temperatures above 1260°C, these precipitates transform to a lamellar phase., Quite early in the development of this alloy, these H. E. McCoy, Influence of Several Metallurgical Variables on the Tensile Properties of Hastelloy N, ORNL-3661 (August 1964). 2 However, more recent precipitates were reasoned to be carbides, studies indicate that these particles may not be carbides. In order to help clariflyy this problem, a small heat of Hastelloy N was made in which part of the carbon atoms were carbon-14. Samples of this alloy were given the varicus heat treatments, which were observed to alter the mechanical properties and subsequent autoradio- graphic studies were carried out. It was felt that this approach would provide the answers to two important questions: (1) are the coarse precipitates and the lamellar phase in Hastelloy N carbides, and (2) how does the carbon distribution in the alloy change with heat treatment and can the changes in mechanical properties be correlated with the carbon distribution? The following report will present the details of this study. EXPERIMENTAL DETATLS A small heat of Hastelloy N was prepared from a charge of commercial air-melted Hastelloy N and a small amount of nickel that had been carburized by heating in a mixture of graphite and BaCO; (carbon atoms present as carbon-14). The charge was nonconsumably arc melted and cast into a 3/8-in,-diam mold. The ingot was sheathed in stainless steel, swaged to 1/4 in, in diameter at 1177°C, and swaged to 1/8 in. in diameter at ambient temperature. The chemical analysis of the resulting heat is given in Table 1. The composition is within the specified limits® for Hastelloy N. The resulting l/8-in.-diam rod was cut into small pieces that were given various heat treatments in argon. The specimens were then prepared for metallographic examination. Eastman NTB Liquid Emulsion was used for the autoradiographic studies and was applied directly on °T, K. Roche, The Influence of Composition Upon the 1500°F Creep-Rupture Strength and Microstructure of Molybdenum-Iron-Nickel- Base Alloys, ORNL-2524 (June 24, 1958). 3J. T. Venard, Tensile and Creep Properties of INCR-8 Ffor the Molten-Salt Reactor Experiment, ORNL-TM-1017 (February 1965). Table 1. Analysis of Experimental Material Element Content (vt %) Nickel 73.4 Chromium 6.34% Iron 3.11 Molybdenum 15.5 Silicon 0.71 Manganese 0.50 Carbon 0.058 the surface of the polished specimen. In order to obtain high resclution, very thin layers of emulsion were used. The emulsion was left undisturbed until the desired exposure was obtained, after which the emulsion was developed in situ. The carbon distribution was determined by microscopic examination of the specimen-emulsion composite. One problem associated with the interpretation of autoradiographs was the fact that when viewed at about 250X, the emulsion was always exposed in "spots" rather than uniformly. The reported grain size for the emulsion is of the order of 1 U and the type of exposure expected would be a uniform darkening even when the developed emulsion is viewed at 1000%X, This apparent inconsistency is as yet unresolved, but the "uniform" exposure has never been observed in any material studied., It is felt that the small spots represent a uniform carbon distribution and that these spots arise because all the material in the emulsion is not capable of being exposed. FEXPERIMENTAL: OBSERVATIONS Figure la shows the microstructure of the material in the as- worked condition. Figure 1lb shows an autoradiograph of the material in the as-worked condition, The carbon seems to be inhomogeneously s Y.61447 ¥ - ' = ¥ - " . e = 1 . - B | - wi . i T 8 . < - oy j . - - - L i - § i = sl 3 i a8 % - " '1 » . . e e - X - i - . 2 - - # p i B # '11' = - - - = ' h - - v ' - i - =3 & e el | & i ] i ek a A - - ¥ - = . i ¥ " - - - o . ™ 4-1-'1 . : \ N » - 4 ' = ] ¥ _' . - e - ¥ -y - § & - L . o e, -..,r . r ’ e .. T i RN, O N M e b v & . R w b ’ = - s ® . e p‘fi" - . | i v s 4 : ! PR T e L ' - i 3 . - - - i i b A ' . i - E ¥ ™ i » ah a ¥ Ir F ) . - . ' » - . " . i ' 1 " ¥ 4 - -y AT ' ) i . » --. = i" . ¢ . * - - e ) - e & i i - — a - .--.c - . g . J . . i \ b b i - - i o g - ' i B g - x ) ) P - i L i F < - i - - .l g X - i ) i 3 =5 - : 3 = ! ' - - w - L - i ¥ o § o - p . F L= 1B . ' I - - b i = . ik = v - . A * = v - | - - %= " - i 2 A = } J i wall L - | . - - i i ' s B < i ! ' g g - Pi' i 5 ¥ s 4 . - . 'K ’ } . 4 ' . . 1 r . M ! J | \ r i a P i - g 1 b (u - - ¥ - ¥ i ¥ - . ¥ i 3 Fig, 1. micrograph of specimen etched with aqua regia. specimen in the as-polished condition, 16-hr exposure. Hastelloy N in the As-Worked Condition. (b) Autoradiograph of 100X, (a) Photo- o r— distributed on a microscale, Figure 2a shows the material after a l-hr anneal at 1177°C, followed by rapid cooling. Figure 2b is an autoradio- graph of the same specimen., This anneal distributes the carbon almost uniformly in the material, although there does seem to be enough grain-boundary segregation to delineate the grain structure. Figure 3a shows the alloy after a l-hr anneal at 1232°C, This photomicrograph is at high enough magnification to resolve the large precipitates that are characteristic of this alloy. The autoradiograph of this specimen is quite similar to that shown in Fig. 2b. However, Fig. 3b shows the autoradiograph at a high magnification. The light spots are the precipitate particles in the alloy, Note that the autoradiograph does not show any darkening above these particles, indicating that they are low in carbon, Figure 4a shows the microstructure which results from a l-hr anneal at 1260°C. Many of the precipitates become associated with grain boundaries so that an almost continuous network results. Figure 4b shows an autoradiograph of this specimen which has a 48-hr exposure. The importance of the exposure time will be shown later. There is a definite segregation of carbon to the grain boundaries. Figure 5a shows the microstructure of a specimen annealed 1 hr at 1316°C. The precipitate particles have transformed almost entirely to the lamellar phase. Figure 5b illustrates the microstructure in greater detail, Figure 6a shows that one constituent of the lamellar product is quite low in carbon and the the other constituent contains about the same amount of carbon as the matrix. Figure 6b shows the grain-boundary phése in a somewhat different morphology, but again, one constituent is low in carbon and the other contains about the same amount of carbon as the matrix. As shown in Fig. 7a, a l-hr anneal at 1371°C increases the con=- centration of the intergranular phase. Figure 7b is an autoradiograph with a 72-hr exposure which indicates that the grain boundaries are enriched in carbon, However, a shorter exposure and the use of a higher magnification help delineate the actual lccation of the carbon. & a;&fi T g iy 0 Y-60189 Fig. 2. Hastelloy N After a l-hr Anneal at 1177°C. (a) Photo- micrograph of specimen etched with aqua regia. (b) Autoradiograph of specimen in the as-polished condition, l6-hr exposure. 100x. Fig. 3. Hastelloy N After a l-hr Anneal at 1232°C. (a) Photo- micrograph of specimen etched with aqua regia. 250x. (b) Autoradiograph of specimen in the as-polished condition, 16-hr exposure. 750x. Fig. 4. micrograph of specimen etched with aqua regia. specimen in the as-polished condition, 48-hr exposure. i Hastelloy N After a l-hr Anneal at 1260°C, ‘ f‘ > - L% Y-63024 . - -, i, ~ . g S -4 = & - - 1 - - G € — - i . - S . = Y -59961 (a) Photo- (b) Autoradiograph of 200 g ; e Mol Y 63025 G'-’ - » .‘! <@ ARy « ‘1 i % » 3 o . " o~ Y-61440 . % il - L\(-?\E; fi'fi"" :l “f' . “ %l 5 h. (A % ¢ . ® L 4 ! ; E d (b ) :. l’- ". ) ! +"r'_ ..,-- ._-* % > . ¥ e a Mg, 5 Hastelloy N After a 1l-hr Anneal at 1316°C. Etched with aqua regia. (a) 250x., (b) 1000x. 10 Y-60257 Fig, 6., Autoradiographs of Hastelloy N After a l-hr Anneal at 1316°C. Exposed in the as-polished condition, 16-hr exposure, 750x. Y59962 Fig. 7. Hastelloy N after a l-hr Anneal at 1371°C. (a) Photomicro- graph etched with aqua regia. (b) Autoradiograph made in the as-polished condition, 72-hr exposure. 250X. 12 Figure 8 shows that the lamellar product in the grain boundary contains a constituent that is low in carbon., The carbon enrichment seems to be adjacent to the grain-boundary product rather than in the grain~boundary phase. Figure 9 shows the microstructure of the alloy after a 1-hr anneal at 1177°C followed by 100 hr at 649°C. Figure 10a and b show that rather gross segregation of carbon to the grain boundaries occurs as a result of this treatment. Annealing for 1 hr at 1260°C followed by 24 hr at 871°C produces the microstructure shown in Fig, lla., The autoradiograph shown in Fig. 11b illustrates the inhomogeneous distribution of carbon in the alloy after this heat treatment. Two pieces of the alloy were rolled into 1 x 1/2 x O.%40-in. sheets. They were fused together by Heliarc welding without the addition of any filler metal. A transverse section of the weld wag prepared for metallographic examination. The base metal has a microstructure similar to that shown in Fig. 1. Figure 12a shows the heat-affected zone and the weld metal., TFigure 12b is an autoradiograph of the area shown in Fig, 1l2a. There does not seem to be any segregation of carbon in the part of the base metal that recrystallized during welding. Near the fusion line, the car- bon segregated to the grain boundaries. Figure 13a is a high magnifica- tion photograph which shows the carbon segregation near the fusion line. Figure 13b shows that the carbon distribution in the weld metal is quite uniform, Two variations in experimental techniques with respect to metallo- graphic study of the weld specimen should be mentioned. First, the weld specimen was etched lightly before the liquid emulsion was applied. This was necessary because the carbon segregation was not sufficient to deline- ate the various regions of the weld. Secondly, the exposure time for the autoradiographs was 300 hr as compared with times of 16 to 72 hr for the other specimens. This resulted from differences in the properties of the NTB Liquid Emulsion. One lot of emulsion was used for the wrought speci- mens and a second lot was used for the weld. By appropriate cross checks 1t was found that both lots of emulsion revealed similar details if the exposure times were varied by a factor of about ten. Fig. 8. Autoradiograph of Hastelloy N after a l-hr Anneal at 1371°C. As-polished condition, l6-hr exposure. 750x. . ¥ XN SR bt Y-63027 ~%i o v'g:_-j_' . "y s . S R e = A --rf(.'.‘.f.{u---.: .,,r\(_\ L 7 E AN e g |'_ ' Y g e RN 7 ':".-t'"}"'i"f -, ‘:rhf ‘r't ¢ t_r"’u!‘ % l‘.rfi...- s . ‘1 - '(( w_ta & - \ y % !.-"r : ’J-‘ "; ,}. 3 0 . s | -‘f"fif"’: ) i Ly ‘r” 2 Mg ' 5 a8 - f' i %‘.‘.‘. 1 ;{:{‘ o ¥ : r; ‘- ]'1- X *..:-3 % ' e R " o “ .::b PR Wi ' 6 TONE " i *'!“?".l & .l’ b.‘_' — <" A ‘i‘q = f v’ o e e aF N Fig. 9. Hastelloy N after a l-hr Anneal at 1177°C Followed by 100 hr at 871°C. Etchant: aqua regia. 14 Fig. 10. Autoradiographs of Hastelloy N After a 1l-hr Anneal at 1177°C Followed by 100 hr at 649°C. As-polished condition. (&) 16-hr exposure. (b) 72-hr exposure. 250x,. 15 » T "= il e T L Y-63028 - & b g™ e - F N = * - . . "o i ™ o - - 5 [ X . = - - B " - % - - - \.-‘ o = & . . o - Ny o [ T m - L i 5 5 = - i ' - o » o - - I - & % - & - J.- - & - ht : v -® - o » -fl; & - % ‘ i . - — . L : - - . y - ‘I ‘; - Fr o ¥ - e - - f ’- i L ‘ - Y 1 F . - - 1 & - ' P B ’ : - . s & K - v o - - N \ / g E . 5 "y - = 5 - e, - ' 2 - \ - T w e w " - V"’ % . T .4 hi“ “ s - E T & 3 2 & . - - o " ra - = . - - - o . - - . N " et - Foaw ) \ \ 2 - B \. : ol v 4 e, e, N - ’ PR - & " .- » . ) - l:f Ty " - - Y 7 ': . Bk » r ke ¥ . - | - - ¥ L - - = Yy . - - i e~y . I s o LSS R o . g wd & . é ¥ st - el # i - = - T » ’ - - = - e S " e - - o - -4 - . g .._‘ e P i - = _gin - - | r" o N - U ‘\. - e o = ’ L - = - - . ‘ - . S { A ¥ - » o e o WA X : = : " - W - » ~ - -~ e - ; % . . 2 . . b = - s = * 5 s ' . -t . & - - - - e :-' . » Y - » 5 C - b, N SR Ay - : - o S - - b B = " i~ -~ ' .._ o A £ 2 ~ ' - - ey oy . & — - - i - - . T . " - - - - .-I -~ - i * - 9 s 3 & - - o-?. ’ 3 -3 3 i = . s 3 ’ & ® 9 o - . - . -‘ - , - . & . - w -, - B - c l. L " - - . > s - - i - - - ' - = (a) ! & - ® ‘- # ¥ oa ot & . o & : - - - s - - x % 3 " s i - ’ NN 0530 -5*-:_ :#:I.“‘ s = i : - » : e & 'i ‘-‘- L. R Fig. 11. Hastelloy N After a l-hr Anneal at 1260°C Followed by 24 hr at 871°C. (a) Photomicrograph of specimen etched with aqua regia. (b) Autoradiograph of specimen in as-polished condition, 72-hr exposure, 250x%. Y-62550 o o 5 L . - i - i A "'1, » % < : 4= T e e '.-‘ t- ¥ : 3 P ‘ f l.," f.'."" "4‘.'?-‘;'.'-. -i-.""g-' ‘)n". wy " '|J : - . £ Ve ij . 1 =X 1 A "-'{.'- = _.l-l * - 2. % L - - J L I § } o ] - T s ‘i i e = Yt YT ) k " - (b) - . P ~N }j I b » - - SR . Fig. 12. Weld Metal and Heat-Affected Zone of a Hastelloy N Weld. () Photomicrograph of specimen etched with aqua regia. (b) Autoradio- graph of specimen after a light etch, 300-hr exposure. 250x. Y-62552 Fig. 13. Autoradiographs of Hastelloy N Welds After a Light Etch, 300-hr Exposure. (a) Heat-affected zone., 750x. (b) Weld metal. 250x. 18 DISCUSSION OF RESULTS The results which have been presented may be summarized as follows: 1. DNeither the coarse precipitate particles which are present as stringers nor the lamellar phase are enriched in carbon. In fact, the coarse precipitate particles and one constituent of the lamellar phase are depleted in carbon with respect to the matrix. 2. The carbon is distributed fairly uniformly at annealing tempera- tures up to 1260°C, 3. At temperatures above 1260°C the carbon is segregated to the grain boundaries, although the areas adjacent to the grain-boundary pre- cipitate are more enriched than the precipitates themselves. 4. Annealing at 1177°C followed by 100 hr at 649°C and annealing at 1260°C followed by 24 hr at £71°C both produced gross segregation of carbon to the grain boundaries. 5. Welding produced some intergranular carbon segregation in a small region of the heat-affected zone. The first observation indicates very strongly that Hastelloy N is not basically a solid-solution alloy and that intermetallic phases are present. There are numerous possibilities of compounds which could be formed from the various alloying elements present. However, the observa- tion that the quantity of precipitate in Hastelloy N does not depend on the concentration of minor alloying elements leads one to believe that the second phase in actually a nickel-molybdenum intermetallic. The binary nickel-molybdenum phase diagram4 shown in Fig. 14 indicates that a binary alloy of 16 wt % Mo and nickel would be single phase up to about 1400°C. However, studies by Lundy on the nickel-rich corner of the nickel- molybdenum-chromium system have shown that the addition of chromium to nickel reduces the solubility of molybdenum in the alloy. This is equi- valent to saying that the alpha filed in Fig. 14 is reduced in size and “Metals Handbook, American Society for Metals, Cleveland, 1948, p. 1230, >T. S. Lundy, A Metallographic and X-Ray Study of Nickel-Base Alloys of 20-25 Per Cent Molybdenum and 3—15 Per Cent Chromium, M.S. Thesis, The University of Tennessee, 1957. £G 19 Y.12802 °C Atomic Percentage Molybdenum °F 20 4 80 2000 0 eo 3600 1800 3200 1600 2800 1460 2400 1200 2000 1000 1600 800 600 1200 400 800 400 a + p ONi 10 20 30 40 30 60 70 80 90 Mo Weight Percentage Molybdenum Fig, 14, DNickel-Molybdenum Equilibrium Diagram. that the alpha and beta fields are moved to the left. Lundy also noted that the addition of chromium suppressed the formation of beta. Recent 6 studies by Norman® on the nickel-molybdenum-iron system have shown that iron has very little effect on the solubility of molybdenum in nickel, but that iron also suppresses beta formation. Both ILundy and Norman noted that the phase transformations in these alloys are quite sluggish. In light of these facts, it is hypothesized that the coarse precipitates that are present in Hastelloy N after fabrication are a modified delta phase which is formed in the melt as it cools. Reheating for 1 hr at 1260°C or at higher temperatures causes the delta to decompose to form alpha and gamma (the lamellar phase). The second, third, and fourth observations which concern carbide segregation indicate that the ductility of this material is not controlled %W. E. Norman and E. E. Stansbury, An Investigation of Nickel-Rich Alloys Containing Molybdenum and Iron, The University of Tennessee (August 1963). 20 by the carbon distribution. The studies reported previously’ showed that the minimum fracture elongation (measured in a tensile test at 871°C) is reduced by a factor of 3 as a result of annealing at 1204°C as compared with that obtained by annealing at 1177°C. Annealing at 1232°C produced another twofold decrease in elongation. However, the autoradiographs show no significant carbon segregation until annealing temperatures of 1260°C were used. Both of the aging treatments that were used (1 hr at 1177°C followed by 100 hr at 871°C, and 1 hr at 1260°C followed by 16 hr at 871°C) produced gross carbide segregation. The material receiving the first heat treatment was found to have about one- half the ductility of the material given the second treatment. From Figs. 9, 10, and 11 it is not obvious that any great difference exists in the degree of carbon segregation. In view of these results, it is felt that the loss in ductility in this alloy does not correlate with the grain-boundary segregation of car- bon. A close examination of the test results’ obtained on various heats of Hastelloy N and the compositions of these various heats leads one to suggest that the troublesome element may be silicon, although no direct evidence exists for this conclusion. The carbon segregation that occurred in the weld can be rationalized in terms of the microstructures that were obtained during 1-hr anneals. The carbon was segregated to the grain boundaries by l-hr anneals above 1260°C. For the short time that heat was applied to the weld, higher temperatures would probably be required to cause carbon segregation. The weld metal did not show any carbon segregation., Hence the observation that the carbon was segregated only in a small region in the heat-affected zone is as expected. 7H. E. McCoy, Influence of Several Metallurgical Variables on the Tensile Properties of Hastelloy N, ORNL-3661 (August 1964). F P 21 SUMMARY AND CONCLUSIONS It has been observed by autoradiographic studies on a heat of Hastelloy N containing carbon-14 that (1) the large precipitates in this alloy are not enriched in carbon, and (2) the loss in ductility cannot be associated with the segregation of carbon. It is hypothesized that the major precipitates in this alloy are nickel-molybdenum intermetallic compounds which form as a result of the solubility of molybdenum in nickel being reduced by the presence of chromium in the alloy. The loss in ductility in this alloy as a result of annealing at elevated tempera- tures is probably associated with a minor alloying element other than carbon. It is hypothesized that silicon is this troublesome element. ACKNOWLEDGMENT The author is grateful to B, J. Massey of the Isotopes Division for assistance in preparing the mixture used to saturate nickel melting stock with carbon-1l4, This study would not have been possible without the Metal Forming and Casting Group who made this alloy. The metallography and auvtoradiography were performed by M. D. Allen and his efforts and perscnal Jjudgement were of great value. The author is also grateful to J. R. Weir, R. 5. Crouse, and D. A, Douglas for reviewing this work and making several helpful suggestions. The Reports Office is acknowledged for their assistance in preparing this document. 23 ORNL-TM-1353 INTERNAL, DISTRIBUTION 1-3, Central Research Library 57. J. H Frye, Jr. 4—5, Reactor Division Library 58, C. H. Gabbard 6. ORNL - Y-12 Technical Library 59, W. R. Gall Document Reference Section 60, R. B. Gallaher 7—16. Laboratory Records Department 6l. R. J. Gray 17. Laboratory Records, ORNL R.C. 62. W. R. Grimes 18. ORNL Patent Office 63. A. G. Grindell 19. G. M. Adamson 6. R. H. Guymon 20, L. G. Alexander 65. G. Hallerman 21, C, F, Baes 66, P. H. Harley 22. S. E. Beall 67. D. G. Harman 23. E. 8. Bettis 68, C, S, Harrill 24, D, S. Billington 69. P. N. Haubenreich 25, F, F, Blankenship 70. P. G. Herndon 26, E. P, Blizard 71-73, M. R. Hill 27. R. Blumberg 7. B, C. Hise 28. A. L. Boch 75. H. W. Hoffman 29, E. G. Bohlmann 76. V. D, Holt 30, C., J. Borkowski 77. P. P. Holz 31, G. E. Boyd 78. A. Houtzeel 32. E. J. Breeding 79. T. L. Hudson 33. R. B. Briggs 80. H. Inouye 34. F., R. Bruce 81, P, R, Kasten 35. G, H. Burger 82. R. J. Kedl 36. S. Cantor 83, T. M. Kegley 37. D. W. Cardwell 84, M. T. Kelley 38. 0. B. Cavin 85. M. J. Kelly 39, J. A. Conlin 86. C. R. Kennedy 40, W, H. Cook 87. A. I, Krakoviak 41. L. T. Corbin 88, J. W. Krewson 42. G, A. Cristy 89, C, E, Lamb 43. R. S. Crouse 90. C. F. Leitten, Jr. 44, J., L. Crowly 91. R. B. Lindauer 45, F, L, Culler 92. R. S. Livingston 46. J. E. Cunningham 93. M. I. Lundin 47. D. G. Davis 9., T. S. Lundy 48, W. W. Davis 95, W. R. Martin 49, J. H. DeVan 96—-105. H, E, McCoy 50, R. G. Donnelly 106, W. B. McDonald 5l. D. A. Douglas 107. C. K. McGlothlan 52. N. E. Dunwoody 108, C. J. McHargue 53. J. R. Engel 109, E. C, Miller 5., E. P. Epler 110. C. A, Mills 55, W, K. Ergen 111, W, R. Mixon 56. A. P. Fraas 112. R. L. Moore 113, J. C. Moyers 136, W. F. Spencer 114, T. E. Northup 137. I, Spiewak 115, W. R. Osborn 138, R. Steffy 116, L. F, Parsly 139, C. E. Stevenson 117, P. Patriarca 140, C. D. Susano 118, H. R. Payne 141. A, Taboada 119, W. B. Pike 142, J. R. Tallackson 120, H. B. Piper 143. E. H. Taylor 121, B, E. Prince 144, R. E. Thoma 122. J. L. Redford 145, G. M, Tolson 123. M, Richardson 146. D. B. Trauger 124, R. C. Robertson 147. R. W. Tucker 125, H. C, Roller 148, W. C. Ulrich 126. M. W, Rosenthal 149, D. C. Watkin 127, H. C. Savage 150. G. M. Watson 128, H. W. Savage 151. B. H. Webster 129, D, Scott 152, J. R. Weir 130, J. H. Shaffer 153, J. H. Westsik 131, E, D, Shipley 154, J. C. White 132, G. M, Slaughter 155, L. V. Wilson 133. A. N. Smith 156, C. H. Wodtke 134, P. G. Smith 157. G. J. Young 135. A. H. Snell EXTERNAL DISTRIBUTION 158. C. M. Adams, Massachusetts Institute of Technology 159-160. D. F. Cope, AEC, ORO 161. C. B. Deering, AEC, ORO 162. R. W. Garrison, AEC, Washington 163. J. L. Gregg, Bard Hall, Cornell University 164. R. W. McNamee, Manager, Research Administration, UCC, New York 165, M. Shaw, AEC, Washington 166. J. M. Simmons, AEC, Washington 167. E. E. Sinclair, AEC, Washington 168. W. L. Smalley, AEC, ORO 169, E. E. Stansbury, University of Tennessee 170. M. J. Whitman, AEC, Washington 171, Division of Research and Development, AEC, ORO 172-186. Division of Technical Information Extension