Materials Science and Engineering Handbook Part 10 pot

Table 5 Resin-matrix composite open-mold processing characteristics Cure operation Process Resin Reinforcement Filler Thermoplastics Thermosets Fiber orientation Pressure (a) Temperature (b) Moving-mold mandrel Filament winding and fiber Wet fiber, winding, prepreg tape Undirectional continuous fiber tape Yes Yes Yes Multidirectional parallel to mandrel Low Low Braiding Wet resin impregnation after winding Continuous fiber Yes Yes Yes Parallel to braid mold surface, multidirectional fibers Medium/high Medium Fabric tape wrapping Prepreg tape Continuous fabric (tape width) Yes Yes Yes Multidirectional, parallel to mandrel surface High Low Stationary-mold mandrel Hand lay- up Prepreg liquid Fiber, fabric mat, short continuous Yes Yes Yes Random, parallel to mold surface Low Low Gun spray- up Liquid Chopped short fiber Yes Yes Yes Random, parallel to mold surface Low Low Fiber-tape lay-down Prepreg tape, wet tape Continuous unidirectional fiber tape Yes Yes Yes Multidirectional, parallel to mandrel Medium Low Pultrusion Wet resin impregnation of fibers during pull through die Continuous fiber, fiber mat Yes Yes Yes Parallel to laminate exterior surface and mold surface Medium Medium Laminated plates, tubes Prepreg Fiber mat, fabric (unidirectional, fiber oriented) Yes Yes Yes Parallel to mold plates High Low Miscellaneous Casting neat resin Liquid resin Powder, short fiber Yes Yes Yes Random, parallel to mold surface Low Low Calendering Semiliquid resin, catalyst, cure agent Fiber, powder Yes Yes No Parallel to sheet surface Medium Low Source: Ref 6, 7, 8, 9, 10, 11 (a) Pressure ranges: low, 100 kPa ( 15 psi); medium, 100-1725 kPa (15-250 psi); high, up to 100 MPa (15 ksi). (b) Temperature ranges: low, room temperature to 165 °C (330 °F); medium, 165-190 °C (330-370 °F); high, 190-205 °C (370-400 °F); very high, 205- 815 °C (400-1500 °F). Table 6 Metal-matrix composite processing Manufacturing process Matrix material Reinforcement material Densification method Final shape operations Powder metallurgy P/M process Aluminum, titanium, or stainless steel powder Silicon carbide powder Temperature, pressure, and time sintering Extrusion Roll sheet, plate Forging Rotating mandrels Cospray of molten matrix and SiC whiskers on rotating mandrel Aluminum, titanium, or stainless steel melt Silicon-carbide whiskers/powder Carbon, boron Spray pressure Mandrel rotation Machine finish Filament wind with fiber and resin/powder matrix Aluminum, titanium, or stainless steel powder Resin (thermoplastic, thermoset) Metal fiber (aluminum, titanium, or stainless steel) prepregged with resin, powder matrix Pressure and temperature on mandrel As wound and surface coated Filament wind with fiber and spray with molten metal matrix (plasma-arc spray) Aluminum, titanium, or stainless steel powder pressure molten spray between fiber layers Metal fiber or man-made fiber (boron, SiC, alumina glass, carbon) filament wound on mandrel Pressure temperature consolidated Removed from mandrel in sheet form and molded to structural shape As molded and surface coated Hot press/diffusion bond Hot, mold of metal/reinforced fiber Aluminum, titanium, or stainless steel foil or thin sheet Glass, carbon, boron, graphite depending on metal melt temperature Mold temperature pressure/inside sealed vacuum retort Machine and finish Diffusion bond Aluminum, titanium, or stainless steel thin foil Metal fiber or man-made fiber (boron, alumina glass, carbon) Wound on steel tube, sealed and evacuated with metal bag Isostatic pressure in furnace Machine and finish Multiple hot press and diffusion bond Aluminum, titanium, or stainless steel thin metal foil Metal fiber or man-made fiber (boron, alumina glass, carbon) Thin-pressed metal-fiber sheets diffusion bonded Sheets superplastic formed to shape with temperature, pressure Machine and finish Compressed preform densified Compressed preform in CVD pyrolytic carbon infiltrated into preform in Preform reinforcement of ceramic, metal, or man-made fibers, in particle, whisker, Vacuum, inert gas purge temperature conversion of organic gas into carbon Machine and CVD furnace CVD furnace short- or long-fiber form deposition and H 2 finish Compressed preform in hot-melt metal matrix Molten metal pressed, vacuumed, or wicked into preform reinforcement Preform reinforcement of ceramic, metal, or man-made fibers, in particle, whisker, short- or long-fiber form Temperature, pressure, time consolidation Forge, extrude, or roll Machine and finish CVD, chemical vapor deposition. Source: Ref 4, 12, 13, 14 Table 7 Carbon-reinforcement/carbon-matrix processing Manufacturing process Matrix material Reinforcement material Densification method Final shape operations Rotating mandrels Three-dimensional woven/filament wound carbon/carbon (also braided) Phenolic, pitch, and furan resins convertible with inert atmosphere heat to densified carbon char Carbon (rayon, pan, pitch base), graphite fiber prior processed to 1650-2760 °C (3000-5000 °F) for fiber weaving dry on a rotating bulk graphite mandrel with radial fibers. Filament- wound axial, hoop fibers Vacuum pressure impregnation with pitch resin 1650 °C (3000 °F) carbonized in inert vacuum. Repeat cycle five times to specific gravity = 1.90 max. Optional final graphitization at 2760 °C (5000 °F). Densification cycles may require up to 1 week Machine and finish after each impregnation and carbonization cycle to open voids for the next densification cycle Two-dimensional fabric tape-wound carbon/carbon Same as three dimensional Prepreg carbon phenolic fabric laid up, vacuum bagged, and cured at 165 °C (325 °F) and 1720 kPa (250 psi) for up to 18 hours. Heat- up, cure, cool down Carbonize billet, vacuum pressure impregnate with pitch resin and cure. Repeat cycle six times to specific gravity = 1.80 max. Final graphitization at 2760 °C (5000 °F) is optional Machine and finish after each impregnation and carbonization cycle may be necessary to open voids for next impregnation Two-dimensional filament wound CVD infiltrated (also braided) CVD of pyrolytic carbon into filament wound fiber preform; more than one densification cycle may be required Carbon or graphite fiber filament wound shape with helical, polar, or hoop windings with or without coupling agent and binder resin CVD of pyrolytic carbon into filament wound fiber preform may take one to five cycles depending on woven preform, density desired, and the surface buildup and penetration. Final graphitization at 2760 °C (5000 °F) is optional Machine and finish after each impregnation may be necessary to open voids for infiltration Static (male/female) open/closed mold mandrel Two-dimensional felt preform CVD infiltrated or resin impregnated; or fabric-sheet lay-up CVD of pyrolytic carbon into fiber felt preform; more than one densification may be required Carbon or graphite short fibers are felted into fiber preform Same as two-dimensional filament wound for rotating mandrels Same as two- dimensional filament wound for rotating mandrels Compressed fiber preform powder, Resin or CVD impregnation or Bulk graphite or graphite Multiple resin/CVD Machine and shape per densification whisker particles both particles preform densification cycles cycle Source: Ref 2, 4, 14, 15 Resin-Matrix Processing Closed mold methods of fabrication are grouped into four families having similar characteristics (Ref 6, 7, 8, 9, 16). Preform molding in transfer, compression, or resin-transfer molds uses a preform of fiber or fabric in a resin matrix. Fiber orientation is parallel to the mold surfaces. Preform flow-die molding by injection, extrusion, or reaction injection uses a preform of fiber or fabric in a resin matrix that is forced through a forming die at high pressure and high temperature and then is cured. Fiber orientation is parallel to the mold centerline or to the mold surfaces. Thin-shell molding by blow molding, rotational molding, or slip casting uses a liquid resin plus a preform of fiber in a resin matrix that is cured with a temperature, pressure, time cure cycle. Fiber orientation is parallel to the mold surfaces. Miscellaneous molding processes such as foam, lost core, and thermoforming use short fibers in a resin matrix that is cured using a cure cycle. Fiber orientation is parallel to the mold surfaces. Open-mold methods are grouped into the following three families by their characteristics (Ref 6, 7, 8, 9). Moving-mold mandrel processes (filament winding, braiding, and fabric-tape wrapping) use a continuous fiber or fabric with a resin matrix that is wound on a moving mandrel and is subsequently cured. Fiber orientation is parallel to the mandrel surface. Stationary-mold mandrel processes (fabric hand lay-up, chopped-fiber gun lay-up, fiber-tape lay-down, fiber pultrusion through a die, fabric structural-shape lamination) use a resin matrix that is cured after the required thickness is achieved. Fiber orientation is parallel to the mandrel surface. Miscellaneous molding processes (such as casting and calendering) use a liquid resin, with or without a fiber reinforcement, shaped to the mold surface by the mold cavity or rollers and cured. Whereas as the closed-mold tooling includes the capacity for pressure and temperature control over time, open-mold processes require additional equipment for the resin-cure cycle such as: • Ovens • Autoclaves (heated pressurized air chambers) • Vacuum bags and bleeder/release materials • Hydroclaves (heated pressurized water and component rubber bags) • Furnaces and induction heaters • Electron-beam or ultraviolet light resin-cure systems The additional curing equipment ensures a uniform distribution of the resin matrix, a highly uniform density, and a high- quality component. Metal-Matrix Processing Metal-matrix processing involves higher temperatures and pressures for laminate metal-matrix solidification than resin- matrix processing does. Both open- and closed-mold presses are used in conjunction with plasma-arc metal-spray equipment. The family of processes used for metal-matrix composites are listed below (Ref 4, 12, 13). Powder Metallurgy. Aluminum, titanium, or stainless steel powder plus fiber reinforcement is compacted at a pressure of 21 to 28 MPa (3 to 4 ksi) and sintered at temperatures up to 1760 °C (3200 °F) to form solid right-cylinder billets in closed molds. Subsequent forming to the final shape is by extrusion, rolling, or forging. Rotating-mandrel processes are used to deposit the following material forms: • Plasma-arc spraying of the metal matrix and gun- spraying of fiber reinforcement for hollow structural shapes • Filament winding of continuous reinforcement fiber and plasma arc spraying of the metal matrix (aluminum, titanium, or stainless steel) for plates and shapes • Filament winding of continuous fiber reinforcement that has been coated with molten metal matrix for plates and shapes The material is processed on the open mandrel under a low pressure (up to 100 kPa, or 15 psi) and at low temperature (up to 165 °C, or 330 °F) for final solidification. The metal mandrel may or may not be removed, depending on the design concept. Hot Pressing and Diffusion Bonding. A matrix of carbon, boron, silicon carbide, stainless steel, or titanium in the form of thin metal foil is reinforced with continuous fiber to form a flat sheet preform, which is subsequently densified by pressure and temperature diffusion bonding. High pressure (up to 100 MPa, or 15 ksi) and ultrahigh metal melt temperature (up to 2760 °C, or 5000 °F) is required for solidification to final shape. Shapes are then machined and final finished. The temperature used depends on the metal matrix and fiber types used. Compressed Reinforcement Preform with Matrix Infiltrations. The preform reinforcement used is usually a metal or organic short fiber pressed into a sheet or solid billet preform, with infiltration of molten aluminum, titanium, or stainless steel by pressure impregnation or carbon infiltration by chemical vapor deposition (CVD). The pressure used may vary from low (0 to 100 kPa, or 0 to 15 psi) for CVD, to high (up to 100 MPa, or 15 ksi) for molten metal, and temperature is very high (up to 2760 °C, or 5000 °F). The temperature used again depends on the metal matrix and fiber types used. Additional process equipment for the metal-matrix composite fabrication includes: • CVD furnaces • Closed molds with temperature, time, and pressure controls • Hot-vacuum, closed-mold presses • Plasma-arc metal spray and powder-gun equipment This equipment ensures a matrix laminate having a uniform density with a minimum of subsurface discontinuities. Carbon/Carbon Matrix Processing Carbon/carbon processing methods involve the use of the highest temperature and pressure open molds and vacuum/inert heating chambers for the multiple-resin pressure-impregnation cycles and the subsequent multiple carbonization/graphitization of the resin and/or CVD densification cycles (Ref 2, 4, 15). Rotating mandrels of bulk graphite are used to deposit a fiber (two- or three-dimensional) lay-down of a reinforcement preform that is subsequently pressure impregnated with a resin, cured, and carbonized. The resin/carbonization cycles may be repeated up to eight times to achieve the density goals. Chemical vapor deposited carbon may also be infiltrated into preform in the late densification cycles as a surface and subsurface strengthening agent and as an oxidation-resistant material. Filament winding, braiding, or fabric-tape wrapping is used to produce two-dimensional fiber preforms or a three- dimensional fiber shape having radial in-wound or drilled/bonded-in-place radial-rod reinforcements. The fiber or fabric can be preimpregnated with resin or post-wind pressure impregnated with resin and then cured. The preform is subsequently carbonized and/or carbon (CVD) densified. This cycle is repeated three to eight times and may be graphitized to a final density of 1.45 to 1.95 g/cm 3 . Static (Male/Female) Open/Closed Mold Mandrels. A fiber mat or a fabric-sheet pattern lay-up is resin transfer molded with resin or carbon CVD densification that is carbonized/graphitized and repeat cycled to the density goal. Alternatively, a fiber preform is placed in a closed chamber and vacuum-pressure resin impregnated, cured, carbonized three to eight times, and graphitized. A variation of this second process is to carbon CVD infiltrate the preform after 2 to 4 cycles of resin char processing. The CVD process is continued for 2 to 3 cycles, with machining/cleaning of the outside surfaces after each cycle to open the preform-billet pores and void areas for further impregnation and densification. Carbon-fiber/carbon-resin-char-matrix processing is accomplished first by a resin-cure cycle at 163 °C (325 °F) and a pressure of 1725 to 6900 kPa (250 to 1000 psi) in a vacuum-bag enclosure. Second, the cured resin is carbonized and graphitized in inert vacuum chambers. Carbonization requires a 1370 to 1930 °C (2500 to 3500 °F) temperature and a time of approximately one week, and graphitization requires a temperature of 2480 to 3040 °C (4500 to 5500 °F) and a one-week period. The reimpregnation of the pores and void cavities of the charred component, after machining the surfaces and cleaning, is at a pressure of 10.3 to 17.2 MPa (1500 to 2500 psi) in an inert vacuum chamber heated to 540 to 1095 °C (1000 to 2000 °F) for less than one week. An occasional carbon (CVD) infiltration into the carbonized preform is performed by processing in an inert vacuum furnace at 1370 to 1930 °C (2500 to 3500 °F) for less than one week. Equipment in addition to the open graphite mandrels for carbon/carbon matrix processing includes carbonization and graphitization furnaces and carbon (CVD) infiltration chambers. In addition, resin-impregnation pots are used to fill the fiber preforms with a pitch or phenolic-resin system. Lathes or large turning machines are used after each densification cycle to prepare a fresh surface for the next resin-impregnation/char-densification cycle and to ensure final dimensional control. The open graphite mandrel is used for fabrication of the carbon/carbon fiber filament-wound preform, while closed chambers are used for the resin impregnation, carbonization, graphitization, and carbon (CVD) infiltration densification cycles. Additional information about processing of composites is provided in the article "Design for Composite Manufacture" in this Volume. References cited in this section 2. Engineered Materials Handbook Desk Edition, ASM International, 1995, p 477, 532-582, 1057-1094 4. Composites, Vol 1, Engineered Materials Handbook, ASM International, 1987, p 118, 119, 355, 360, 363, 373, 381, 405, 410, 861, 862 6. R. Flinn and P. Trojan, Engineering Materials and Applications, Houghton-Mifflin, 1990, p 618, 619 7. Handbook of Advanced Material Testing, Marcel Dekker, 1995, p 945-948, 950, 955 8. E.P. DeGamo, Materials and Processes in Manufacturing, 4th ed., Macmillan, 1974, p 190-212 9. C.A. Harper, Ed., Handbook of Plastics, Elastomers and Composites, 2nd ed., McGraw- Hill, 1992, sections 1.5, 4.4, 5.31, 11.2 10. R.B. Seymour, Reinforced Plastics, ASM International, 1991, p 9, 51 11. "Fiberglass Reinforced Plastics," Owens-Corning Corp., 1964, p 24-30 12. C.T. Lynch and J.P. Kershaw, Metal Matrix Composites, CRC Press, 1972, p 16, 17, 51 13. K.A. Lucas and H. Clarke, Corrosion of Alumina Based Metal Matrix Composites, John Wiley & Sons, 1993, p 17, 20, 21 14. Carbon Composite and Metal Composite Systems, Vol 7, Technomic 15. G. Savage, Carbon-Carbon-Composites, Chapman Hall, 1993, p 95, 97, 98, 101, 125, 126, 129, 200 16. L. Edwards and M. Endean, Manufacturing with Materials, Butterworths, 1990, p 73, 145 Effects of Composition, Processing, and Structure on Properties of Composites R. Laramee, Intermountain Design Inc. Mechanical Properties of Composites Within a composite laminate consisting of a reinforcing fiber/fabric, fillers, coupling agent and resin, metal, or carbon- matrix system, the greatest influence on mechanical properties is the reinforcement type and its percentage of the total constituents. That is, among composite components that have the same fiber orientation in the laminates and the same matrix material, the component having the highest-strength fiber and the greatest percentage (by weight) of fiber in the laminate will exhibit the greatest strength. Likewise, in the component, the highest strength exists in the planes with the highest percentage of fiber (Fig. 1). For a three-dimensional block, strength is greatest in the vertical and axial fiber directions. For a two-dimensional block, strength is greatest in the axial direction. The decrease in laminate strength with an increase in temperature, as shown in Fig. 4 and 5 for glass and carbon fibers in an epoxy-resin matrix, is caused by the softening and a weight loss of water and solvent in the resin system. Resin weight loss begins at 120 to 175 °C (250 to 350 °F), and resin conversion to a porous char state begins at 315 to 760 °C (600 to 1400 °F). Resin matrix carbon retention for carbon matrix conversion at 760 °C (1400 °F) is 55% for phenolic, 17% for polyester, and 10% for epoxy (novolac). Fiber strength does not degrade significantly until the following temperatures are reached: Temperature Fiber °C °F Kevlar 160 320 Glass 430 800 Al 2 O 3 1200 2200 Boron 1650 3000 SiC 1650 3000 Resin-matrix composites (as well as metal- and carbon-matrix composites) are used in many aerospace and military applications at temperatures below -20 °C (0 °F) and above 760 °C (1400 °F). The resin-matrix composite having the best elevated-temperature properties is carbon fiber (highest degradation temperature) in phenolic resin (highest resin matrix carbon retention). Fig. 4 Effect of temperature on the strength of S-glass-fiber/epoxy-matrix composites. (a) Tensile strength. (b) Elastic modulus. Source: Ref 4 Fig. 5 Effect of temperature on the strength of carbon-fiber/epoxy-matrix composites. (a) Tensile strength. (b) Elastic modulus. Source: Ref 4 The strengths of metal-matrix composites using three different nonferrous alloys as the matrix materials are shown in Table 8. As can be seen, the titanium alloy provides higher strength and modulus (and higher density and cost) than the aluminum-alloy matrix. Of the available reinforcing fibers, boron, glass, and carbon provide the highest composite strengths, while graphite, silicon carbide (SiC), and aluminum oxide (Al 2 O 3 ) provide the highest composite modulus. Table 8 Typical mechanical properties of metal-matrix composites Reinforcement Tensile strength (b) Tensile modulus (b) Matrix material (a) Material Form Content, vol % MPa ksi GPa 10 6 psi None . . . . . . 306 44 70 10 T-300 carbon Fiber 35-40 1034-1276 (L) 150-185 (L) 110-138 (L) 16-20 (L) 1490 (L) 216 (L) 214 (L) 31 (L) Boron Fiber 60 138 (T) 20 (T) 138 (T) 20 (T) Aluminum (6061-T6) SiC Powder 20 552 80 119 17 Aluminum (201) GY-70 carbon Fiber 37.5 793 (L) 115 (L) 207 (L) 30 (L) [...]... Engineered Materials Handbook, ASM International, 1987, p 118, 119, 355, 360, 363, 373, 381, 405, 410, 861, 862 5 H.S Katz, and J.V Milewski, Handbook of Fillers for Plastics, Van Nostrand, 1987, p 56, 57, 75 6 R Flinn and P Trojan, Engineering Materials and Applications, Houghton-Mifflin, 1990, p 618, 619 7 Handbook of Advanced Material Testing, Marcel Dekker, 1995, p 945-948, 950, 955 8 E.P DeGamo, Materials. .. Effects of Composition, Processing, and Structure on Properties of Composites R Laramee, Intermountain Design Inc References 1 P.K Mallick, Materials Manufacturing and Design, Fiber Reinforced Composites, 2nd ed., Marcel Dekker, 1993, p 16, 71, 213, 289, 301, 373, 390, 476-478, 533 2 Engineered Materials Handbook Desk Edition, ASM International, 1995, p 477, 532-582, 105 7 -109 4 3 Modern Plastics Encyclopedia,... chopped-fiber length on the mechanical and thermal properties of E-glass/phenolic composites Fiber length Notched izod impact strength Tensile strength J/m ft · lbf/in MPa ksi MPa ksi GPa 106 psi MPa ksi 30-65 0.6-1.2 55-83 8-12 69 -103 101 5 13.824.1 2.03.5 241276 3540 1.5-2.5 6 320-426 6-8 83 -103 1215 103 138 1520 13.817.2 2.02.5 241276 3540 1.5-2.5 13 80 0106 5 15-20 83- 110 1216 138207 2030 17.220.7 2.53.0... Introduction SURFACE ENGINEERING is a multidisciplinary activity intended to tailor the properties of the surfaces of engineering components so that their function and serviceability can be improved The ASM Handbook defines surface engineering as "treatment of the surface and near-surface regions of a material to allow the surface to perform functions that are distinct from those functions demanded from the... in this article can be found in Surface Engineering, Volume 5 of ASM Handbook (Ref 1) Reference 1 Surface Engineering, Vol 5, ASM Handbook, ASM International, 1994 Effects of Surface Treatments on Materials Performance Arnold R Marder, Lehigh University Solidification Surface Treatments Solidification surface treatments include hot dip coatings, weld overlays, and thermal spray coatings Hot Dip Coatings... Existing materials and fabrication methods for composite design should be used wherever possible to control the unknown factors involved in advancedconcept applications It is important to have a thorough understanding of the following factors for composite material applications: • • • The material composition and the percentage (by weight) of all constituents and the storing, shipping, and handling... strength and impact resistance (see Fig 7) with good damping characteristics and low cost but a high density (1.90-2 .10 g/cm3) Graphite offers lower strength and impact resistance; it also exhibits a high modulus, thermal stability, good oxidation resistance at temperature, and a light weight (1.32-1.90 g/cm3), but at a higher cost Density is an important factor in part- quality inspection and achieving... this section 1 P.K Mallick, Materials Manufacturing and Design, Fiber Reinforced Composites, 2nd ed., Marcel Dekker, 1993, p 16, 71, 213, 289, 301, 373, 390, 476-478, 533 4 Composites, Vol 1, Engineered Materials Handbook, ASM International, 1987, p 118, 119, 355, 360, 363, 373, 381, 405, 410, 861, 862 15 G Savage, Carbon-Carbon-Composites, Chapman Hall, 1993, p 95, 97, 98, 101 , 125, 126, 129, 200 Effects... Lucas and H Clarke, Corrosion of Alumina Based Metal Matrix Composites, John Wiley & Sons, 1993, p 17, 20, 21 14 Carbon Composite and Metal Composite Systems, Vol 7, Technomic 15 G Savage, Carbon-Carbon-Composites, Chapman Hall, 1993, p 95, 97, 98, 101 , 125, 126, 129, 200 16 L Edwards and M Endean, Manufacturing with Materials, Butterworths, 1990, p 73, 145 17 J.A Lee and D.L Mykkanen, Metal and Polymer... at 100 °C (212 °F) for 72 h References cited in this section 1 P.K Mallick, Materials Manufacturing and Design, Fiber Reinforced Composites, 2nd ed., Marcel Dekker, 1993, p 16, 71, 213, 289, 301, 373, 390, 476-478, 533 7 Handbook of Advanced Material Testing, Marcel Dekker, 1995, p 945-948, 950, 955 12 C.T Lynch and J.P Kershaw, Metal Matrix Composites, CRC Press, 1972, p 16, 17, 51 17 J.A Lee and . in this section 2. Engineered Materials Handbook Desk Edition, ASM International, 1995, p 477, 532-582, 105 7 -109 4 4. Composites, Vol 1, Engineered Materials Handbook, ASM International, 1987,. 119, 355, 360, 363, 373, 381, 405, 410, 861, 862 6. R. Flinn and P. Trojan, Engineering Materials and Applications, Houghton-Mifflin, 1990, p 618, 619 7. Handbook of Advanced Material Testing,. 945-948, 950, 955 8. E.P. DeGamo, Materials and Processes in Manufacturing, 4th ed., Macmillan, 1974, p 190-212 9. C.A. Harper, Ed., Handbook of Plastics, Elastomers and Composites, 2nd ed., McGraw- Hill,