CN102171374A - Heat-resistant magnesium alloy - Google Patents
Heat-resistant magnesium alloy Download PDFInfo
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- CN102171374A CN102171374A CN200980139157XA CN200980139157A CN102171374A CN 102171374 A CN102171374 A CN 102171374A CN 200980139157X A CN200980139157X A CN 200980139157XA CN 200980139157 A CN200980139157 A CN 200980139157A CN 102171374 A CN102171374 A CN 102171374A
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- C22C23/00—Alloys based on magnesium
- C22C23/02—Alloys based on magnesium with aluminium as the next major constituent
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- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/06—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of magnesium or alloys based thereon
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Abstract
The present invention provides a heat-resistant magnesium alloy which contains Mg as the main component and further contains Al, Ca and Mn and which has a metal structure composed of Mg grains and grain-boundary precipitates present in the grain boundaries among the Mg grains. The grain-boundary precipitates consist of mixed-crystal phases which are composed of Laves-phase compounds having C14-type crystal structure and Laves-phase compounds having C36-type crystal structure. At least in the interfaces between the Mg grains and the grain-boundary precipitates, the relative angles (alpha) between the normal vectors to the basal planes of hexagonal crystals of the Mg grains and the normal vectors to the basal planes of hexagonal crystals of the grain-boundary precipitates fall is within the range of 88 to 92 DEG. Since the magnesium alloy has a metal structure which is less susceptible than conventional magnesium alloys to basal slip, the magnetic alloy rarely causes basal slip even at high temperature and exhibits high mechanical characteristics even in high-temperature atmosphere.
Description
Technical field
The present invention relates to bear on the pyritous basis, the heat-resistant magnesium alloy that uses under the high loading.
Background technology
Than the viewpoint of the lighter magnesium alloy of aluminium alloy quality, be widely used as flyer material, vehicle material etc. from lighting always.But magnesium alloy is according to the purposes difference, and its intensity and thermotolerance are all not enough, therefore, require its characteristic further to improve.
Therefore, in patent documentation 1 (TOHKEMY 2004-162090 communique) and patent documentation 2 (TOHKEMY 2004-232060 communique) magnesium alloy that contains calcium (Ca) and aluminium (Al) is disclosed an amount ofly.In these documents, at the crystal boundary of the Mg of magnesium alloy crystal grain, Ca-Al compound, Mg-Ca compound are separated out crystallization or are separated out, and therefore can stop the motion of dislocation.Its result, though magnesium alloy at high-temperature area, creep strain is also less, thereby shows excellent thermotolerance.And then above-mentioned magnesium alloy is by making the Mn solid solution in Mg crystal grain, with the magnesium alloy solution strengthening.
Summary of the invention
The metal structure of alloy can influence its characteristic greatly.Therefore, in order to obtain showing better stable on heating magnesium alloy, be necessary to make the kind of for example adding element, also have the suitable metal structure of controlling of addition.The object of the present invention is to provide and a kind ofly use suitable alloying element to control the metal structure of magnesium alloy and show the magnesium alloy of excellent heat resistance.
Magnesium and a lot of magnesium alloy have close-packed hexagonal structure (hcp) shown in Figure 1.In the hcp metal, will { the 0001} face be as slipping plane, is easy to take place the distortion due to (slip direction for＜11-20＞) owing to slide in the bottom surface as the bottom surface of close filling face.Slide and at room temperature can not take place substantially in the such non-bottom surface of statuary column face slip.Fig. 2 is the temperature dependent figure of the critical shearing stress of slip of expression bottom surface and the slip of non-bottom surface.Known to { the 0001} face slides other faces as the bottom surface slip factor of slipping plane and just can take place with littler shearing force as the non-bottom surface of slipping plane, slide and be easy to take place owing to temperature raises to become in non-bottom surface.That is, non-bottom surface slip easy generation unlike sliding in the bottom surface, sliding resistance is big.
, if slide distortion, then crystal structure produces dislocation.At this moment, the quantity of the dislocation of generation (dislocation desity) has the upper limit, and in the hcp metal, the dislocation that the bottom surface slides that results from is in the great majority.This is because as mentioned above, the easier generation of bottom surface slip factor non-bottom surface slip.Therefore, the inventor etc. expect if in the whole dislocations that take place, and make to result from the shared ratio of dislocation that non-bottom surface slides and increase, and the shared ratio of sliding in the bottom surface that the deflection that then results from is big of dislocation will reduce, and then improves mechanical characteristics.In addition, the raising of the known mechanical characteristics that produces by this mechanism is very remarkable when high temperature.And then, carried out deep research, new discovery as a result be easy to take place metal structure that slides non-bottom surface and the composition that is used to achieve, thereby invented heat-resistant magnesium alloy of the present invention.
Promptly, heat-resistant magnesium alloy of the present invention, it is characterized in that, with magnesium (Mg) is principal constituent, contain aluminium (Al), calcium (Ca) and manganese (Mn), have by Mg crystal grain and the metal structure that constitutes at the crystal boundary crystalline crystal boundary crystallisate of this Mg crystal grain, aforementioned crystal boundary crystallisate is made of mutually the mixed crystal of C14 type crystal structure with the Laves' phases compound of C36 type crystal structure, at least at the interface of aforementioned Mg crystal grain and aforementioned crystal boundary crystallisate, the relative angle of the normal line vector of the normal line vector of the hexagonal system bottom surface of this Mg crystal grain and the hexagonal system bottom surface of this crystal boundary crystallisate is 88 °～92 °.
In addition, above-mentioned " C14 type " reaches " C36 type ", and " C15 type " described later is the symbol of Strukturberichte periodical, represents MgZn2, the MgCu2 in the Laves' phases, 3 kinds of similarly basic crystal structures of MgNi2 representative respectively.
In addition, so-called in this specification sheets " thermotolerance " is that mechanical properties (for example, being kept creep properties that test obtains or hot strength etc. by stress relaxation test, axial force) with the magnesium alloy in high-temperature atmosphere is estimated.
The metal structure of heat-resistant magnesium alloy of the present invention is made of Mg crystal grain and crystal boundary crystallisate.The crystal boundary crystallisate is made of mutually the mixed crystal of C14 type crystal structure with the Laves' phases compound of C36 type crystal structure, and therefore, the compound that constitutes the crystal boundary crystallisate is not separated, and is monocrystalline in fact substantially.Consequently the crystal boundary crystallisate is high-intensity crystallisate.In addition, even mixed crystal at high temperature also is stable mutually.
In addition, at least at the interface of Mg crystal grain and crystal boundary crystallisate, if the relative angle of the normal line vector of the normal line vector of the hexagonal system bottom surface of Mg crystal grain and the hexagonal system bottom surface of crystal boundary crystallisate is 88 °～92 °, the slip of then non-bottom surface is got for the bottom surface slip and is easy to take place, and slides and suppressed in the bottom surface that deflection is big.Think that it be the reasons are as follows: Mg crystal grain is surrounded by the high strength crystal boundary crystallisate that is made of mutually above-mentioned mixed crystal, and the crystalline orientation of Mg crystal grain and crystal boundary crystallisate is with restrained in the almost rectangular relation in both interfaces at least.At this moment, can infer that Mg crystal grain becomes the such affined crystal grain of distortion that is slided and caused by the bottom surface in the difficult generation of Mg intragranular.Especially at high temperature, the critical shear force rate room temperature of sliding in non-bottom surface is little, and therefore, the occurrence frequency that slides in the non-bottom surface under the high temperature becomes big, thereby can suppress bottom surface slip distortion.
That is, contain the heat-resistant magnesium alloy of the present invention of above-mentioned alloying element, compare, have the metal structure that is difficult for taking place the bottom surface slip, slide, therefore, be presented at the higher mechanical characteristics in the high-temperature atmosphere even be difficult for also that at high temperature the bottom surface takes place with existing magnesium alloy.
Description of drawings
Fig. 1 is the synoptic diagram of close-packed hexagonal structure.
Fig. 2 is the temperature dependent figure of the critical shearing stress of expression bottom surface slip (dotted line) and non-bottom surface slip (solid line).
Fig. 3 be between the normal line vector of hexagonal system bottom surface of the normal line vector of hexagonal system bottom surface of expression Mg crystal grain and crystal boundary crystallisate relation schematically illustrate figure.
Fig. 4 is the metal structure photo with the test film # 01 section of the observed embodiment of metalloscope.
Fig. 5 is the metal structure photo with the observation sample of the observed #01 of transmission electron microscope (TEM).
Fig. 6 is the metal structure photo of observation sample of the #C1 of the comparative example that arrives with tem observation.
Fig. 7 is dark-field scanning transmission electron microscope (DF-STEM) image of the observation sample of #01.
Fig. 8 is the DF-STEM image of the observation sample of #C1.
Fig. 9 represents TEM image and the electronogram with the observation sample of the observed #01 of transmission electron microscope (TEM).
Figure 10 represents the diffraction pattern of observation sample of the #01 that obtains with TEM and the comparative result of mimic diagram.
Figure 11 is expression stress relaxation test result's figure.
Figure 12 is the crystalline orientation image of the crystalline orientation of the test film # 01 behind the expression stress relaxation test.
Figure 13 be expression make a zone in the crystalline orientation image of Figure 12 become understandable candy strip dualization figure and at the explanatory view of this regional crystalline orientation.
Figure 14 be expression make other zones in the crystalline orientation image of Figure 12 become understandable candy strip dualization figure and at the explanatory view of this regional crystalline orientation.
Figure 15 is the explanatory view of the distortion of expression bottom surface sliding body.
Embodiment
Below, the preferred forms that is used to implement heat-resistant magnesium alloy of the present invention (being designated hereinafter simply as " magnesium alloy ") is described.
Magnesium alloy of the present invention is a principal constituent with magnesium (Mg), contains aluminium (Al), calcium (Ca) and manganese (Mn), has by Mg crystal grain and the metal structure that forms at the crystal boundary crystalline crystal boundary crystallisate of this Mg crystal grain.
The crystal boundary crystallisate is made of mutually the mixed crystal of C14 type crystal structure with the Laves' phases compound of C36 type crystal structure.C14 type crystal structure and C36 type crystal structure be hexagonal system each other, is easy to form the mixed crystal phase.Mixed crystal phase Laves' phases compound is the sort of crystal structure that the composition metallic element is closely clogged, so it ad infinitum approaches monocrystalline, therefore, is successive on the crystal boundary crystallisate microcosmic, and the area of crystal boundary, number of die are minimum.That is, the reticulation structure (three-dimensional mesh configuration) that has in the crystal boundary crystallization of Mg crystal grain on the crystal boundary crystallisate macroscopic view, even and then in the inside of reticulation, crystallization also is to exist continuously.The intensity of crystal boundary in the metal structure is improved, be reinforced as a whole.At this moment, optimal situation is that the reticulation structure of crystal boundary crystallisate hides more than 70% of Mg crystal particle crystal boundary (this value abbreviates " hiding rare of reticulation " as) that is revealed as wire in the section in zone about magnesium alloy 400 μ m * 600 μ m.
Have the reticulation structure even have the magnesium alloy crystal boundary crystallisate of the present invention of above-mentioned crystal boundary crystallisate, also different with brilliant discontinuous, the present magnesium alloy that constitutes of brief summary with its inside.For example, as alloying element, in the magnesium alloy that does not contain Mn, form the reticulation structure though macroscopic view goes up the crystal boundary crystallisate in the crystal boundary crystallization of Mg crystal grain, can't see the crystal boundary crystallisate on the microcosmic has continuity.
And at least at the interface of Mg crystal grain and crystal boundary crystallisate, the relative angle of the normal line vector of the normal line vector of the hexagonal system bottom surface of Mg crystal grain and the hexagonal system bottom surface of crystal boundary crystallisate is 88 °～92 °.Fig. 3 is the schematic illustration that is illustrated in the relation between the normal line vector of hexagonal system bottom surface of the normal line vector of the hexagonal system bottom surface interface, Mg crystal grain of Mg crystal grain and crystal boundary crystallisate and crystal boundary crystallisate.In Fig. 3, hexagonal mesh of white is hexagonal mesh of the crystal boundary crystallisate that forms mutually of the mixed crystal by the C14 type crystal structure and the Laves' phases compound of C36 type crystal structure, and black six grid are hexagonal mesh of Mg crystal grain.Arrow A is the normal line vector A of the sub-bottom surface of white hexagonal mesh, and arrow B is the normal line vector B of the bottom surface of black hexagonal mesh.For magnesium alloy of the present invention, normal line vector A meets at right angles substantially with the angle α that normal line vector B is become, and is 88 °～92 °.The angle that normal line vector became can be calculated from the measurement result of electron diffraction, X-ray diffraction, Electron Back-Scattered Diffraction etc.
If at least at the interface of Mg crystal grain and crystal boundary crystallisate, both crystalline orientations are in above-mentioned relation, and then at the intragranular of Mg crystal grain, the occurrence frequency that slides in the bottom surface that deflection is big reduces, and the ratio of sliding in the non-bottom surface that sliding resistance is big and deflection is little increases.Therefore, the mechanical characteristics of magnesium alloy of the present invention improves.Especially at high temperature (150～200 ℃), about 1/2nd (with reference to the zones that are represented by dotted lines among Fig. 2) the when critical shear of sliding in non-bottom surface is room temperature, therefore, the raising effect of the mechanical characteristics when high temperature is significant.
In addition, optimal situation is that the crystal boundary crystallisate is formed by the Mg-Al-Ca based compound.Mg
2Ca is a C14 type crystal structure, infers that the Al solid solution is in Mg
2Ca and the mixed crystal that forms C14 type crystal structure and C36 crystal structure are mutually.At this moment, mixed crystal mutually in the content of C14 type crystal structure greater than the content of C36 type crystal structure.
Mg crystal grain is surrounded by above-mentioned crystal boundary crystallisate and exists.At this, if have same crystalline orientation substantially, even will in the scope that high-angle boundary forms, see a kind of Mg crystal grain as, even then at the intragranular of this Mg crystal grain, the relative angle of the normal line vector of the normal line vector of the hexagonal system bottom surface of Mg crystal grain and the hexagonal system bottom surface of crystal boundary crystallisate also belongs to 88 °～92 ° scope substantially.The median size of this Mg crystal grain is preferably below 500 μ m, more preferably below 200 μ m.The particle diameter of Mg crystal grain is more little, is easy to bring into play the effect of the generation reduction that makes the bottom surface slip more.The crystalline orientation that " has same crystalline orientation substantially " in addition, in this manual for having apart from reference plane ± 2 °.
Mg crystal grain can contain tabular precipitate at intragranular.Tabular precipitate stops the intragranular dislocation moving of Mg.Produces owing to dislocation moves on slipping plane, thus crystalline to be out of shape can be to be Mg crystalline { the tabular precipitate that the 001} face is parallel with hexagonal crystal Mg crystalline c face.In addition, its thickness of slab of tabular precipitate is 2～20nm, and thickness of slab is thick more, can improve mechanical characteristics more.In addition, precipitate can be the Laves' phases compound formation by C15 type crystal structure.This is owing to predicting that { the 111} face is easy to form mutual stable interface on the crystallography to Mg crystalline c face and C15 structure, promotes the formation of tabular precipitate.The compound that constitutes the precipitate with this crystal structure can be Al-Ca based compound and/or Mg-Al-Ca based compound.
In addition, the shape of precipitate, crystal structure and composition can utilize transmission electron microscope (TEM) to observe, and can observe and measure by the element image that utilizes electron diffraction and energy dispersion type x ray fluorescence spectrometry (EDX).
Magnesium alloy of the present invention can also have particulate at the intragranular of Mg crystal grain.Particulate is at the Mg intragranular, be present in substantially tabular precipitate around.Even think that this particulate is present in the Mg intragranular, directly do not help to improve the intragranular intensity of Mg yet.But, the existence of particulate relevant with the generation of precipitate (aftermentioned), particulate is the particulate that for example contains the such Mn of Al-Mn based compound.
In addition, particulate is subsphaeroidal, and particle diameter is about 10～15nm.In addition, the existence of particulate can be observed by dark-field scanning transmission microscope (DF-STEM) and confirm.
Magnesium alloy of the present invention with above such metal structure contains principal constituent Mg and as Al, Ca and the Mn of alloying element.Especially magnesium alloy of the present invention will be in the time will totally being made as 100 atom %, preferably contain Ca 1.235 atom %～2.470 atom %, the atomic ratio of Al and Ca (Al/Ca) 1.34～1.63, Mn 0.13 atom %～0.27 atom %, rest part is made of Mg and unavoidable impurities.
The common cooling curve that solidifies operation (air cooling) during from castings that casting is formed by magnesium alloy of the present invention, (temperature is respectively T1, T2 and T3, wherein T1＞T3, T2＞T3) to occur 3 temperature stagnation points as can be known.The temperature of molten metal is if reach liquidus temperature (temperature that begins to solidify: T1=600 ℃～620 ℃), then primary crystallization Mg (Mg crystal grain) crystallization.In addition, prediction is if reach T2, and then Al and Mn react and generate the particulate that high temperature generates compd A l-Mn based compound.Secondly, if reach eutectic temperature T3, then with eutectic Mg together, crystallization goes out to form the crystal boundary crystallisate of reticulation.But, the result by the ultimate analysis of carrying out particulate contains the Mn of Duoing than theoretical value as can be known.That is, can predict in the temperature range lower than T3 that Al separates from particulate (Al-Mn based compound), isolating Al follows the aggegation that is dissolved in the intragranular Ca of Mg and forms compound with Ca and separate out.
Al forms compound with the Ca reaction, is the element with this structure of C15 type pressgang, but at the Mg with this structure of C14 type pressgang
2Under the overriding condition of Ca, the Al solid solution is in Mg
2Form this structure of C14 type pressgang and the mixed crystal of this structure of C36 type pressgang among the Ca thus mutually.
When Al/Ca pressed atomic ratio measuring less than 1.34, the content of Ca was many, and the castibility variation is therefore not preferred.And if Al/Ca presses atomic ratio measuring and surpasses 1.63, then the crystal boundary crystallisate is difficult to become the mixed crystal phase, only is easy to form the crystal grain that is made of this structure of C36 type pressgang and is separated, and is therefore not preferred.And then C36 type crystal structure then is easy to undergo phase transition (ScriptaMaterialia51 (2004) 1005-1010) to C15 type crystal structure if be exposed to high temperature.Block aggegation takes place at high-temperature area in C15 type crystal structure easily, and does not form successive crystallisate reticulation on the microcosmic, so the mechanical characteristics during high temperature significantly descends.More preferably the Al/Ca value is 1.42～1.56 by atomic ratio measuring.
Mn and Al react under the temperature higher than T3, and are difficult to fusing in Mg, therefore, are suitable as the alloying element of magnesium alloy of the present invention.In addition, Mn and Al only generate compound between T1 and T3.
In containing of Mn during proportional less than 0.13 atom %,, be difficult to form the normal line vector of both hexagonal system bottom surfaces with desired angle at the interface of Mg crystal grain and crystal boundary crystallisate.In addition, a lot of Al combine with Mn but are residual, and as the crystal boundary crystallisate, be easy to form the crystal grain that only has not this structure of C36 type pressgang of constructing, and be separated for mixed crystal, so not preferred.And if Mn contain the proportional 0.27 atom % that surpasses, the compound that then contains Mn is separated out in the crystal boundary crystallisate, the situation that has reticulation to disconnect is therefore not preferred.Being more preferably containing of Mn proportional lower limit is more than the 0.15 atom %.The upper limit of the Mn that is more preferably is below the 0.25 atom %.
Ca and Mg all are the elements that form C14 and this structure of C36 type pressgang.Ca contain proportional less than 1.235 atom % the time, do not generate precipitate, crystal boundary crystallisate fully, the raising effect of heat-resistant quality is insufficient, and is therefore not preferred.And if Ca contain the proportional 2.470 atom % that surpass, then the growing amount of precipitate, crystal boundary crystallisate is too much, exists in situation about going wrong in the post-treatment, and is therefore not preferred.More preferably Ca to contain proportional be 1.54 atom %～2.16 atom %.
Magnesium alloy of the present invention is not limited to common gravity casting, compression casting, can be die casting.In addition, the mold that uses in casting can be husky mold, metal die etc.The speed of cooling of solidifying in the operation is not limited especially yet, can in air atmosphere, place cooling.
The purposes of magnesium alloy of the present invention is representative with space, military affairs, aviation field, spreads all over various fields such as automobile, household appliances.But, effectively utilize its thermotolerance, more preferably with used for magnesium alloy of the present invention in the product that under hot environment, uses, for example be disposed at engine, variator, idle call compressor or these the related product of automobile engine nacelle.Specifically, the turbo-supercharger of cylinder head, cylinder body, oil pan, oil engine that can enumerate oil engine is with the variator that uses in pump impeller, the automobile etc. etc.
More than, the embodiment of heat-resistant magnesium alloy of the present invention has been described, but the present invention is not limited to above-mentioned embodiment.In the scope that does not break away from purport of the present invention, can those skilled in the art can change according to having implemented, the variety of way of improvement etc. implemented.
Below, the embodiment that enumerates heat-resistant magnesium alloy of the present invention specifically describes the present invention.
Making has changed 2 kinds of test films of the content (addition) of the Al in the magnesium alloy, Ca and Mn, observes and resolve the metal structure of these test films, and carries out stress relaxation test.
The manufacturing of test film
With the fusing assistant of chlorination system be coated in electric furnace preheating the inner face of iron crucible, drop into pure magnesium matrix metal, pure Al, the Mg-Mn alloy as required of having weighed therein, make the above-mentioned substance fusing.Then, the Ca that has weighed is added to (molten metal modulating process) in this molten metal that remains on 750 ℃.
This molten metal is stirred fully, raw material is fully melted after, under same temperature, leave standstill and keep for some time.In this fusing operation, for preventing the burning of Mg, to molten metal surface injecting carbon dioxide gas and SF
6The mixed gas of gas, and suitably fusing assistant is sprinkling upon the molten metal surface.
The various alloyed metal liquid that will obtain according to above-mentioned order inject the metal die (cast operation) of regulation shape, make it solidify (solidifying operation) in air atmosphere.Make the test film of 30mm * 300mm * 40mm like this by gravity casting.The test film that obtains is designated as #01 (embodiment that contains Mn), #C1 (comparative example that does not contain Mn).The chemical constitution of each test film is as shown in table 1.In addition, in the magnesium alloy of table 1 was formed, rest part was Mg.
Table 1
In addition, in table 1, the unit of the alloy composition of #01 and #C1 uses " atom % ".In the molten metal modulating process, the value of " atom % " in the table 1 is scaled " quality % " comes raw materials weighing.In addition, put down in writing the composition of AZ91D (ASTM standard) in the lump.
The observation of metal structure and parsing
The observation of Mg crystal grain and crystal boundary crystallisate [1 ,]
The test film # 01 that makes with the metal microstructure sem observation.Fig. 4 is the metal structure photo with the section of the observed #01 test film of metalloscope.The crystal boundary of observing Mg crystal grain (dark part) and Mg crystal grain has the crystal boundary crystallisate (bright part) that exists with the reticulation shape.In addition,, observe the section of #C1 test film, also can obtain the metal structure photo same with Fig. 1 though do not illustrate.That is, arbitrary test film all can be observed the crystal boundary crystallisate of reticulation shape.
The observation of crystal boundary crystallisate [2 ,]
In order to observe microtexture,, use transmission electron microscope (TEM) to observe with the laminate observation sample of shape of test film # 01 and #C1 with metalloscope observed crystal boundary crystallisate.
Fig. 5 and Fig. 6 are respectively the metal structure photos of the observation sample of the #01 that arrives with tem observation and #C1.Observe the crystal grain boundary that both all have the crystal grain of the primary crystallization Mg more than 2 to adjoin each other.In Fig. 5 (#01), crystal boundary crystallisate (black part) is grown into sheet (stratiform), is successive.In Fig. 6 (#C1), the crystal boundary crystallisate partly disconnects, and is discontinuous.In addition, the fraction of coverage of the reticulation of #01 is about 90%.
In addition, Fig. 7 and Fig. 8 observe dark-field scanning transmission microscope (DF-STEM) image that the crystal boundary crystallisate of the observation sample of #01 and #C1 obtains.The #01 test film do not see as shown in Figure 7 and being separated, and the #C1 test film has been seen as shown in Figure 8 and being separated.For the DF-STEM image of Fig. 7 and Fig. 8, if utilize energy dispersion type x ray fluorescence spectrometry (EDX) to obtain the element image, then in Fig. 7 (#01), Mg, Al and Ca distribute equably, in Fig. 8 (#C1), in the crystal grain that is separated with granular aggegation, the concentration height of Al.And, obtained the electron diffraction of C36 type crystal structure from the high crystal grain of Al concentration.On the other hand, in Fig. 7 and Fig. 8, the crystallization that distributes equably respectively from Mg, Al and Ca has mainly obtained the electronogram of C14 type crystal structure, although a part is not separated, has occurred 2 times to the diffraction spot of the C36 type crystal structure in C14 type crystal structure cycle.That is, as can be known the crystallization that distributes equably of Mg, Al and Ca be C14 type crystal structure with the mixed crystal of C36 type crystal structure mutually, seem to be almost monocrystalline.Thereby, in the #01 test film, be successive on the crystal boundary crystallisate microcosmic of formation reticulation, seem to be almost monocrystalline.On the other hand, in the #C1 test film, forming reticulation even crystal boundary crystallisate macroscopic view goes up, also is discontinuous on the microcosmic, and only the Laves' phases compound that is made of C36 type crystal structure is separated and exists.
In addition, though not shown, even, also observe the crystal boundary crystallisate with TEM for the magnesium alloy of the content of Mn among the #01 being changed into 0.09 atom %.According to the DF-STEM image that obtains, as can be known if increase the amount of Mn, then become block aggegation seen in #C1 (Fig. 8) and reduce and extend and be zonal compound such situation that occupies the majority, but when Mn content is 0.09 atom %, do not see observed continuity among the #01 (Fig. 7).
[3, the orientation of Mg crystal grain and crystal boundary crystallisate measure]
In order to measure the crystalline orientation of Mg crystal grain and crystal boundary crystallisate, use TEM to come viewing test sheet #01.The result as shown in Figure 9.Fig. 9 is the TEM image and the electronogram of the observation sample of the #01 that arrives with tem observation.In addition, diffraction pattern is the limits vision diffraction pattern in the specialized range (being equivalent to the part that with dashed lines surrounds in the TEM image) at the interface of crossing over Mg crystal grain and crystal boundary crystallisate.
Next, the diffraction pattern that obtains is carried out indexing and geometry calculating.The comparative result of expression diffraction pattern and the analog image that obtains from Theoretical Calculation among Figure 10.In addition, diffraction pattern shown in Figure 10 is the same with the diffraction pattern of Fig. 9.In addition, in Figure 10, usefulness * expression forbidden reflection.The known diffraction pattern that obtains be from the diffraction of the Mg of Mg crystal grain with from the overlapping and synthetic of the diffraction of the Mg compound of crystal boundary crystallisate.
More specifically, the result of parsing diffraction pattern is: Eulerian angles (Φ, the Θ of the crystalline orientation of expression crystal boundary crystallisate, Ψ) be (90,51.2,0), (Φ, Θ Ψ) are Φ=0, Θ=-90 ± 2,5≤Ψ≤10 to the Eulerian angles of the crystalline orientation of expression Mg crystal grain.That is, the relative angle of the hexagonal system bottom surface normal line vector of the hexagonal system bottom surface normal line vector of Mg crystal grain and crystal boundary crystallisate is 88 °～92 °.In addition, in this manual, Eulerian angles are conversion of z-y-z axle rotation, and the turning axle of benchmark as shown in Figure 1.In Fig. 1 down to arrow (X-axis) along hexagonal crystal 0001} towards in face of direction prolong (promptly＜11-20＞direction).
[stress relaxation test]
Each test film for being made by test film # 01, #C1 and AZ91D carries out stress relaxation test, checks the thermotolerance (creep properties) of magnesium alloy.Stress relaxation test is to be determined in the duration of test test film is applied the process that the stress of loading when producing the deflection of regulation together reduces in time.Specifically, in 150 ℃ air atmosphere, to the stress under compression of test film load 100Mpa, the mode according to keeping the displacement of test film this moment regularly along with the process of time, reduces its stress under compression.
The alloy composition and the stress of stress relaxation test after 40 hours of each test film of expression among Figure 11.Test film # 01 compares with other test films, and the minimizing ratio of the stress of being loaded is few especially, even at high temperature, has also shown very high creep resistant.So, resolve the crystalline orientation of testing back test film # 01 by Electron Back-Scattered Diffraction (being also referred to as EBSD or EBSP), check displacement model.EBSD measures the crystalline orientation of polycrystalline material and the device of its distribution.In parsing, use by the SEM main frame: system JSM-6490LA of Jeol Ltd. and EBSD resolution system: TSL company (Tex SEMLaboratories, Inc.) the SEM/EBSD device of the automatic resolution system composition of system High Speed EBSD Detector and OIM.As pre-treatment, the grinding of implementing to have used the Ar ionic fluid by the cross section polishing instrument SM-09010 of Jeol Ltd.'s system to carry out to the sightingpiston of test film #01.The result that pretreated #01 test film is recorded with above-mentioned SEM/EBSD device as shown in figure 12.
Figure 12 is the crystalline orientation image of the crystalline orientation of the test film # 01 behind the expression stress relaxation test.In addition, the crystalline orientation image is an angle of only representing the specialized range (being ± 2 ° in this mensuration) from predetermined surface with same color.That is, Figure 12 was the crystalline orientation of representing with color differentiating originally.The crystalline orientation image of observing test film # 01 shown in Figure 12 is divided into 7 zones, has the candy strip of representing with different colours in the zone.In addition, even observe other positions, also seen zone mostly with candy strip or tartan design.
Figure 13 is that expression makes a zone in the crystalline orientation image of Figure 12 become the dualization of understandable candy strip.For example, in Figure 13, the zone that with dashed lines surrounds is the zone of having seen the candy strip of pink colour system in the script green, and by having carried out dualization, green becomes white, and candy strip becomes black.At this, the numeric data according to the crystalline orientation of EBSD illustrates white and black crystalline orientation separately in the drawings, forms the relation of right figure among Figure 13.Child and the white portion of white hexagonal mesh, black hexagonal mesh is partly corresponding respectively with black.Before the stress relaxation test, hexagonal mesh of identical crystalline orientation is configuration regularly basically, but black hexagonal mesh because the load of stress under compression, with＜-1-120＞direction serve as spool ° to be rotated with β=88.If this relative orientation is changed with the Eulerian angles mark, then be (80.6,17.2,25.4), (Φ, Θ Ψ) all have numerical value.
In addition, Figure 14 is that expression makes other zones in the crystalline orientation image of Figure 12 become the figure of the dualization of understandable candy strip.For example, in Figure 14, the zone that with dashed lines surrounds is the zone of having seen the candy strip of intense violet color in the script lilac, and by having carried out dualization, the zone of lilac becomes white and candy strip becomes black.At this, the numeric data according to the crystalline orientation of EBSD illustrates white and black crystalline orientation separately in the drawings, then forms the relation of left figure among Figure 14.White hexagonal mesh and white portion, black hexagonal mesh is partly corresponding respectively with black.Before the stress relaxation test, hexagonal mesh subbase present regulations ground of identical crystalline orientation configuration, but black hexagonal mesh serve as an inclination γ=4 ° with＜10-10＞direction because the load of stress under compression.If this relative orientation is changed with the Eulerian angles mark, then use (0,0,52.4), promptly (0,0, represent that Ψ) Ψ has numerical value.
At this, also have will only take place the relative orientation of the bottom surface Deformation structure of sliding change situation with the Eulerian angles mark (0,0, Ψ).But the sliding interface that form this moment is to form abreast with the hexagonal crystal bottom surface.The relative orientation variation is the variation that Φ and Θ have numerical value in the tissue behind stress relaxation test shown in Figure 13, and it is with only different for the distortion of bottom surface slip as can be known.On the other hand, the candy strip in the zone shown in Figure 14 is similar with the variation of only representing the bottom surface slip with the Eulerian angles mark.But, confirm that sliding interface in this case is the side of hexagonal system, therefore, be difficult to imagine the distortion (shown in Figure 15) that only is in the bottom surface slip of bottom surface for sliding interface.That is, the candy strip that occurs in the crystalline orientation image in this mensuration all hints the right and wrong bottom surface relevant Deformation structure of slip.Therefore, observed same candy strip in the vast scope of test film #01, with (0,0, Ψ) represent the variation of relative orientation, and sliding interface unconfirmed is the zone parallel with the hexagonal crystal bottom surface.That is, test film #01 at high temperature gets for the bottom surface slip and is easy to take place non-bottom surface and slide, and what slided in the bottom surface is inhibited, and has consequently shown higher creep resistant.
Claims (5)
1. a heat-resistant magnesium alloy is characterized in that, (Mg) is principal constituent with magnesium, contains aluminium (Al), calcium (Ca) and manganese (Mn), have by Mg crystal grain and the metal structure that forms at the crystal boundary crystalline crystal boundary crystallisate of this Mg crystal grain,
Described crystal boundary crystallisate is made of mutually the mixed crystal of C14 type crystal structure with the Laves' phases compound of C36 type crystal structure, at least at the interface of described Mg crystal grain and described crystal boundary crystallisate, the relative angle of the normal line vector of the normal line vector of the hexagonal system bottom surface of this Mg crystal grain and the hexagonal system bottom surface of this crystal boundary crystallisate is 88 °～92 °.
2. heat-resistant magnesium alloy according to claim 1, wherein, described crystal boundary crystallisate is formed by the Mg-Al-Ca based compound.
3. heat-resistant magnesium alloy according to claim 1, wherein, described mixed crystal mutually in, the content of C14 type crystal structure is more than C36 type crystal structure.
4. according to each the described heat-resistant magnesium alloy in the claim 1～3, wherein, in the time will totally being made as 100 atom %, contain 1.235 atom %～2.470 atom % Ca, with the atomic ratio of Ca be 1.34～1.63 Al, and the Mn of 0.13 atom %～0.27 atom %, rest part is made of Mg and unavoidable impurities, and described and atomic ratio Ca is Al/Ca.
5. heat-resistant magnesium alloy according to claim 4, wherein, containing Mn is 0.15 atom %～0.25 atom %.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2008-258405 | 2008-10-03 | ||
| JP2008258405A JP5445820B2 (en) | 2008-10-03 | 2008-10-03 | Heat resistant magnesium alloy |
| PCT/JP2009/067318 WO2010038893A1 (en) | 2008-10-03 | 2009-09-29 | Heat-resistant magnesium alloy |
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| CN102171374A true CN102171374A (en) | 2011-08-31 |
| CN102171374B CN102171374B (en) | 2013-07-03 |
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| US (1) | US20110176955A1 (en) |
| EP (1) | EP2365102B1 (en) |
| JP (1) | JP5445820B2 (en) |
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| WO (1) | WO2010038893A1 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105296831A (en) * | 2015-11-05 | 2016-02-03 | 南阳师范学院 | High-room-temperature-elongation wrought magnesium alloy and preparation method thereof |
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| JP6013755B2 (en) * | 2012-04-10 | 2016-10-25 | サンデンホールディングス株式会社 | Compression function member and method of manufacturing the same |
| CN103834838B (en) * | 2012-11-27 | 2016-04-27 | 比亚迪股份有限公司 | A kind of magnesium lithium alloy and preparation method thereof |
| JP6895587B2 (en) * | 2018-06-08 | 2021-06-30 | ジヤトコ株式会社 | Case |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1249355A (en) * | 1998-09-30 | 2000-04-05 | 玛志达株式会社 | Magnesium alloy forged material and member, and method for mfg. forged member |
| JP2001316753A (en) * | 2000-05-10 | 2001-11-16 | Japan Steel Works Ltd:The | Magnesium alloy and magnesium alloy member excellent in corrosion resistance and heat resistance |
| JP2004232060A (en) * | 2003-01-31 | 2004-08-19 | Toyota Industries Corp | Heat resistant magnesium alloy for casting and heat resistant magnesium alloy casting |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2741642B2 (en) * | 1992-03-25 | 1998-04-22 | 三井金属鉱業株式会社 | High strength magnesium alloy |
| JP3522963B2 (en) * | 1996-04-04 | 2004-04-26 | 三井金属鉱業株式会社 | Method for producing heat-resistant magnesium alloy member, magnesium alloy used therefor, and magnesium alloy molded member |
| JP2004162090A (en) * | 2002-11-11 | 2004-06-10 | Toyota Industries Corp | Heat resistant magnesium alloy |
| JPWO2008120497A1 (en) * | 2007-04-03 | 2010-07-15 | 株式会社豊田自動織機 | Heat resistant magnesium alloy |
-
2008
- 2008-10-03 JP JP2008258405A patent/JP5445820B2/en not_active Expired - Fee Related
-
2009
- 2009-09-29 US US13/121,876 patent/US20110176955A1/en not_active Abandoned
- 2009-09-29 WO PCT/JP2009/067318 patent/WO2010038893A1/en active Application Filing
- 2009-09-29 CN CN200980139157XA patent/CN102171374B/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1249355A (en) * | 1998-09-30 | 2000-04-05 | 玛志达株式会社 | Magnesium alloy forged material and member, and method for mfg. forged member |
| JP2001316753A (en) * | 2000-05-10 | 2001-11-16 | Japan Steel Works Ltd:The | Magnesium alloy and magnesium alloy member excellent in corrosion resistance and heat resistance |
| JP2004232060A (en) * | 2003-01-31 | 2004-08-19 | Toyota Industries Corp | Heat resistant magnesium alloy for casting and heat resistant magnesium alloy casting |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105296831A (en) * | 2015-11-05 | 2016-02-03 | 南阳师范学院 | High-room-temperature-elongation wrought magnesium alloy and preparation method thereof |
| CN105296831B (en) * | 2015-11-05 | 2017-09-12 | 南阳师范学院 | A kind of wrought magnesium alloy of high room temperature elongation percentage and preparation method thereof |
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| US20110176955A1 (en) | 2011-07-21 |
| EP2365102B1 (en) | 2015-11-25 |
| JP2010090405A (en) | 2010-04-22 |
| EP2365102A4 (en) | 2014-01-15 |
| CN102171374B (en) | 2013-07-03 |
| JP5445820B2 (en) | 2014-03-19 |
| EP2365102A1 (en) | 2011-09-14 |
| WO2010038893A1 (en) | 2010-04-08 |
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