1、Designation: C 1495 07Standard Test Method forEffect of Surface Grinding on Flexure Strength of AdvancedCeramics1This standard is issued under the fixed designation C 1495; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the effectof surface grinding on the flexure strength of advancedceram
3、ics. Surface grinding of an advanced ceramic materialcan introduce microcracks and other changes in the nearsurface layer, generally referred to as damage (See Fig. 1).Such damage can result in a changemost often adecreasein flexure strength of the material. The degree ofchange in flexure strength i
4、s determined by both the grindingprocess and the response characteristics of the specific ceramicmaterial. This method compares the flexure strength of anadvanced ceramic material after application of a user-specifiedsurface grinding process with the baseline flexure strength ofthe same material. Th
5、e baseline flexure strength is obtainedafter application of a surface grinding process specified in thisstandard. The baseline flexure strength is expected to approxi-mate closely the inherent strength of the material. The flexurestrength is measured by means of ASTM standard flexure testmethods.1.2
6、 Flexure test methods used to determine the effect ofsurface grinding are C 1161 Test Method for Flexure Strengthof Advanced Ceramics at Ambient Temperatures and C 1211Test Method for Flexure Strength of Advanced Ceramics atElevated Temperatures.1.3 Materials covered in this standard are those advan
7、cedceramics that meet criteria specified in flexure testing standardsC 1161 and C 1211.1.4 The flexure test methods supporting this standard(C 1161 and C 1211) require specimens that have a rectangularcross section, flat surfaces, and that are fabricated with specificdimensions and tolerances. Only
8、grinding processes that arecapable of generating the specified flat surfaces, i.e. planargrinding modes, are suitable for evaluation by this method.Among the applicable machine types are horizontal andvertical spindle reciprocating surface grinders, horizontal andvertical spindle rotary surface grin
9、ders, double disk grinders,and tool-and-cutter grinders. Incremental cross-feed, plunge,and creep-feed grinding methods may be used.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establ
10、ish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 1145 Terminology of Advanced CeramicsC 1161 Test Method for Flexural Strength of AdvancedCeramics at Ambient TemperatureC 1211 Test Method
11、 for Flexural Strength of AdvancedCeramics at Elevated TemperaturesC 1239 Practice for Reporting Uniaxial Strength Data andEstimating Weibull Distribution Parameters for AdvancedCeramics1This test method is under the jurisdiction of ASTM Committee C28 onAdvanced Ceramics and is the direct responsibi
12、lity of Subcommittee C28.02 onReliability.Current edition approved Feb. 1, 2007. Published February 2007. Originallyapproved in 2001. Last previous edition approved in 2006 as C 1495 06.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceas
13、tm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.FIG. 1 Microcracks Associated with Grinding (Ref. 1)1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.C 1322 P
14、ractice for Fractography and Characterization ofFracture Origins in Advanced CeramicsC 1341 Test Method for Flexural Properties of ContinuousFiber-Reinforced Advanced Ceramic Composites3. Terminology3.1 Materials Related:3.1.1 advanced ceramic, na highly engineered, high-performance, predominately n
15、onmetallic, inorganic, ceramicmaterial having specific functional attributes. C 11453.1.2 baseline flexure strength, nin the context of thisstandard, refers to the flexure strength value obtained afterapplication of a grinding procedure specified in this standard.3.1.2.1 DiscussionFor the advanced c
16、eramics to whichthis this standard is applicable, the baseline flexure strength isexpected to be a close approximation to the inherent flexurestrength.3.1.3 ceramic matrix composite, na material consisting oftwo or more materials (insoluble in one another) in which themajor, continuous component (ma
17、trix component) is a ceramic,while the secondary component(s) (reinforcing component)may be ceramic, glass-ceramic, glass, metal, or organic innature. These components are combined on a macroscale toform a useful engineering material possessing certain proper-ties or behavior not possessed by the in
18、dividual constituents.C 13413.1.4 grinding damage, nany change in a material that isa result of the application of a surface grinding process.Amongthe types of damage are microcracks (Fig. 1), dislocations,twins, stacking faults, voids, and transformed phases.3.1.4.1 DiscussionAlthough they do not r
19、epresent internalchanges in microstructure, chips and surface pits, which are amanifestation of microfracture, and abnormally large grindingstriations are often referred to as grinding damage. Residualstresses that result from microstructural changes may also bereferred to as grinding damage.3.1.5 i
20、nherent flexure strength, nthe flexure strength of amaterial in the absence of any effects of surface grinding orother surface finishing process, or of extraneous damage thatmay be present. The measured inherent flexure strength maydepend on the flexure test method, test conditions, and speci-men si
21、ze.3.1.5.1 DiscussionFlaws due to surface finishing or ex-traneous damage may be present but their effect on flexurestrength is negligible compared to that of “inherent” flaws inthe material.3.1.6 materials lot or batch, na single billet or severalbillets prepared from defined homogeneous quantities
22、 of rawmaterials passing simultaneously through each processing stepto the end product is often referred to as belonging to a singlelot or batch.3.1.6.1 DiscussionThere is no assurance that a singlebillet is internally homogenous or that billets belonging to thesame lot or batch is identical.3.2 Gri
23、nding Process RelatedDefinitions in this sectionapply to grinding machines and modes that generate planarsurfaces. Applicable grinding machines types are identified in(1.4). Some definitions may not be applicable when used inconnection with non-planar grinding modes such as centerlessand cylindrical
24、 modes which are outside of the scope of thisstandard.3.2.1 blanchard grinding, na type of rotary grinding inwhich the workpiece is held on a rotating table with an axis ofrotation that is parallel to the (vertical) spindle axis.3.2.2 coolant, nusually a liquid that is applied to theworkpiece and/or
25、 wheel during grinding for cooling, removalof grinding swarf, and for lubrication.3.2.3 coolant flow rate, nvolume of coolant per unit timedelivered to the wheel and workpiece during grinding.3.2.4 creep-feed grinding, na mode of grinding character-ized by a relatively large wheel depth-of-cut and c
26、orrespond-ingly low rate of feed.3.2.5 cross-feed, nincrement of displacement or feed inthe cross-feed direction.3.2.6 cross-feed direction, ndirection in the plane ofgrinding which is perpendicular to the principle direction ofgrinding. (Fig. 2)3.2.7 down-feed, nincrement of displacement or feed in
27、the down feed direction. (Fig. 2)3.2.8 down-feed direction, ndirection perpendicular to theplane of grinding for a machine configuration in which thegrinding wheel is located above the workpiece. (Fig. 2)3.2.9 down-grinding, nA condition of down-grinding issaid to hold when the velocity vector tange
28、nt to the surface ofthe wheel at points of first entry into the grinding zone has acomponent normal to and directed into the ground surface ofthe workpiece. (Fig. 3a)3.2.10 dressing, na conditioning process applied to theabrasive surface of a grinding wheel to improve the efficiencyof grinding.3.2.1
29、0.1 DiscussionDressing may accomplish one ormore of the following: 1) removal of bond material fromaround the grit on the surface of the grinding wheel causing thegrit to protrude a greater distance from the surrounding bond,2) removal of adhered workpiece material which interfereswith the grinding
30、process, removal of worn grit, 3) removal ofbond material thereby exposing underlying unworn grit, and 4)fracture of worn grit thereby generating sharp edges.FIG. 2 Machine Axes for Horizontal Spindle ReciprocatingSurface GrinderC14950723.2.11 grinding axis, nany reference line along which theworkpi
31、ece is translated or about which it is rotated to effect theremoval of material during grinding.3.2.12 grinding direction, nwhen used in reference toflexure test bars, refers to the angle between the long (tensile)axis of the flexure bar and the path followed by grit in thegrinding wheel as they mov
32、e across the ground surface. Seelongitudinal grinding direction and transverse grinding direc-tion. (Fig. 4)3.2.13 grit depth-of-cut, nnominal maximum depth thatindividual grit on the grinding wheel penetrate the workpiecesurface during grinding. Synonymous with undeformed chipthickness.3.2.14 in-fe
33、ed, nsynonymous with wheel depth-of-cut anddown feed.3.2.15 longitudinal grinding direction, ngrinding direc-tion parallel to the long axis of the flexure bar. (Fig. 4a)3.2.16 machine axes, nreference line along which trans-lation or about which rotation of a grinding machine compo-nent (table, stag
34、e, spindle.) takes place. (Fig. 2)3.2.17 planar grinding, na grinding process which gen-erates a nominally flat (plane) surface.3.2.18 reciprocating grinding, nmode of grinding inwhich the grinding path consists of a series of linear bi-directional traverses across the workpiece surface.3.2.19 rotar
35、y grinding, nmodes of planar grinding inwhich the grinding path in the plane of grinding is an arc,effected either by rotary motion of the workpiece or of thegrinding wheel.3.2.19.1 DiscussionGrinding striations left on the work-piece surfaces are arcs.3.2.20 surface grinding, na grinding process us
36、ed togenerate a flat surface by means of an abrasive tool (grindingwheel) having circular symmetry with respect to an axes aboutwhich it is caused to rotate. (Fig. 2)3.2.21 table speed, nspeed of the grinding machine tablecarrying the workpiece usually measured with respect to themachine frame.3.2.2
37、2 transverse grinding direction, ngrinding directionperpendicular to the long axis of the flexure bar. (Fig. 4b)3.2.23 truing, nprocess by which the abrasive surface of agrinding wheel is brought to the desired shape and is madeconcentric with the machine spindle axis of rotation.3.2.24 undeformed c
38、hip thickness, nmaximum thicknessof a chip removed during grinding, assuming that the chip isdisplaced from the surface without deformation or change inshape.3.2.24.1 DiscussionEquivalent in size to grit depth-of-cut.3.2.25 up-grinding, na condition of up-grinding is said tohold when the velocity ve
39、ctor tangent to the surface of thewheel at points of first entry into the grinding zone has acomponent normal to and directed out of the ground surface ofthe workpiece. (Fig. 3b)3.2.26 wheel depth-of-cut, ndepth of penetration of thegrinding wheel into the workpiece surface as it moves parallelto th
40、e surface to remove a layer of material. (Fig. 3)3.2.26.1 DiscussionOften abbreviated to depth-of-cut.3.2.27 wheel specifications, ndescription of the grindingwheel dimensions, grit type, grit size, grit concentration, bondtype, and any other properties provided by the wheel manu-facturer that chara
41、cterize the grinding wheel.3.2.28 wheel surface speed, ncircumferential speed of thegrinding wheel surface at points which engage the workpieceduring the process of grinding.3.3 Surface Finish Related:3.3.1 lay, nrefers to the direction a non-random pattern ofsurface roughness in the plane of the su
42、rface, e.g. the directionof abrasive striations on a surface prepared by grinding. (Fig.2)FIG. 3 Relative Wheel and Workpiece Directions of Motion forDown Grinding and Up Grinding FIG. 4 Grinding Directions with Respect to Flexure BarOrientationC14950733.3.2 roughness, nthree-dimensional variations
43、in surfacetopography characterized by wavelengths in the plane of thesurface that are small compared to the design dimensions of theworkpiece.3.3.3 waviness, nsurface topographic variations charac-terized by wavelengths in the plane of the surface that are largecompared to the roughness but smaller
44、than the design dimen-sions of the workpiece.3.4 Flexure Test Related:3.4.1 break force, nforce at which a test specimen frac-tures (fails) in a flexure test.3.4.2 flexural strength, na measure of the ultimatestrength of a specified beam in bending. C 11453.4.3 tensile face, nside of a flexure test
45、specimen that isstressed in tension in a flexure test.Other terms related to flexure testing can be found in C 1161.3.5 Fractography Related:3.5.1 crack, nas used in fractography, a plane of fracturewithout complete separation. C 13223.5.2 flaw, na structural discontinuity in an advancedceramic body
46、 which acts as a highly localized stress riser.C 13223.5.3 fractography, nmeans and methods for characteriz-ing a fractured specimen or component. C 11453.5.4 fracture origin, nthe source from which brittlefracture commences. C 11453.5.5 fracture mirror, nas used in fractography of brittlematerials,
47、 a relatively smooth region in the immediate vicinityof and surrounding the fracture origin. C 1322Other terms related to fractography can be found in C 1322.3.6 Statistical Analysis Related:Terminology related to the reporting of flexural strength dataand Weibull distribution parameters can be foun
48、d in C 1239.4. Summary of Test Method4.1 This method compares the flexure strength of an ad-vanced ceramic material that has been subjected to a user-applied surface grinding process with the baseline flexurestrength for the same material. The baseline flexure strength isobtained after application o
49、f a grinding process specified in thisstandard and is expected to approximate closely the inherentflexure strength of the material. The user-applied surfacegrinding process may result in a decrease in flexure strength,no change in flexure strength, or in certain cases an increase inflexure strength. Two procedures, A and B, are availabledepending on the objective of the measurement. ProcedureAisrestricted to linear grinding processes obtained, for example,by a horizontal spindle, reciprocating-table surface grinder. Inlinear gri
