CN106929786B - A kind of big thickness is nanocrystalline-preparation method of the surface graded layer of Ultra-fine Grained-coarse-grain - Google Patents
A kind of big thickness is nanocrystalline-preparation method of the surface graded layer of Ultra-fine Grained-coarse-grain Download PDFInfo
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Abstract
The invention discloses a kind of preparation method of the surface graded layer of big thickness nanocrystalline ultra-fine crystalline substance coarse-grain, including following steps：On sheet metal of the thickness more than 1mm, first the ultra-fine crystal layer of grade thickness and Ultra-fine Grained coarse-grain gradient layer are obtained with multiple quickly cooling mixing yoghurt method；Ultra-fine crystal layer is uniformly hit with high energy ball beam obtain the surface graded layer of big thickness nanocrystalline ultra-fine crystalline substance coarse-grain again.A kind of preparation method of the surface graded layer of big thickness nanocrystalline ultra-fine crystalline substance coarse-grain of the present invention, the structure feature of prepared surface graded layer are：From outward appearance to inner essence successively in nanocrystalline deformation states Ultra-fine Grained recrystallize the original state coarse-grain multiple gradients continuous transition of the ultrafine crystal deformed state coarse-grain of state, the thickness of entire gradient layer reach millimeter magnitude and surface and inside all without crackle, hole the defects of structure.
Description
Technical field
The present invention relates to metal material processing, modification and Gradient Materials preparation fields, and in particular to a kind of big thickness
The preparation method of nanocrystalline-surface graded layer of Ultra-fine Grained-coarse-grain.
Background technology
Across scale uneven texture is configured as a kind of new structural material mentality of designing, it breaks through traditional material and uniformly closes
Aurification, block crystal grain refinement etc. are modified thoughtcast, and coupling optimization between different attribute and unit is had both by the heterogeneous unit of structure
Mode improves the mechanical properties such as the strength of materials, plasticity, antifatigue damage, anti-friction abrasion, real-life asset is exhausted, environment is disliked
Low energy consumption, high performance demand have been catered under the background condition of change.Surface machinery nanometer in Metal material surface modification method
Change and its prepared Gradient Materials just belong to the scope.So far, making Nano surface copper alloy, aluminium alloy, steel, titanium and
Preparing craft, material refinement mechanism, microstructure characteristic, mechanics and the load metamorphism machine of numerous metal materials such as titanium alloy
System, physical property are also by depth profiling.But most of work therein is for laboratory basic research, handled material
Material is confined to thin plate of the thickness less than 4mm, thin stick of the diameter less than 8mm, and size is much smaller than engineering actually big component.Prepared
Nano-crystalline layers thickness is usually no more than 50 μm, and gradient deformation layer thickness is also limited to tens to hundreds of microns.For mechanical property
It can study, in the style of test, surface hard layer proportion is even up to 100% higher than 20%.
Surface rolling (SMGT/SMRT) is numerous surface machineries such as grinding class (SMAT), shot-peening class (SP), circulation impact class
A kind of method of thicker deformation layer can be prepared in method for making Nano, still, this method is less efficient, needs cycle multiple tracks for a long time
It is secondary, and it deforms layer thickness and also is difficult to larger breakthrough.For example, the deformation layer thickness of cycle rolling gained reaches in fine copper
To 500-700 μm, reach 450 μm in pure nickel, can reach 800 μm in 316L stainless steels, about 460 μm in pure titanium.For in engineering
Thicker component, though surface layer compressive residual stress can inhibit quick forming core, expansion and the fatigue life for improving material of source of damage.
But the total volume fraction that the surface graded layer of only hundreds of microns accounts for material is relatively low, either surface hard layer directly strengthen still
Geometry necessity dislocation pile up in gradient zones is strengthened, all very limited to the contribution of component overall mechanical properties.Moreover, by multiple
During the Coupling Deformation that miscellaneous stress/strain state is dominated, nearly surface layer is difficult to macro with the long-range internal stress of strain gradient
The center portion coarse-grain for seeing long distance plays invigoration effect.Such as academy of sciences's force dawn thunder et al. (Extraordinary strain
hardening by gradient structure,Procedings of the National Academy of
Sciences,2014；111:7197-7201) the gradient-structure IF steel prepared through surface mechanical attrition, for the original plate of 1mm
Material thickness, gradient layer accounting are 24%, and integrally-built yield strength~200MPa is far above the 70MPa of pure coarse grain material, but
Be, if the gradient layer is formed on the plank of 5mm, gradient layer accounting be only 4.8% and structure integral yield intensity only~
88MPa。
It is conceived to the tough improvement for waiting antibody Monoclonals destructive characteristics of the practical large-thickness component of engineering, there is an urgent need to existing for we
Exploitation can prepare the big thickness gradient layer of grade or the new method across the more gradient layers of scale on the basis of Method And Principle.
Invention content
Based on above-mentioned technical problem, the present invention provides a kind of big thickness it is nanocrystalline-the surface graded layer of Ultra-fine Grained-coarse-grain
Preparation method, this method are first prepared using multiple quickly cooling mixing yoghurt at the ultra-fine crystal layer and deep thickness of grade thickness
Ultra-fine Grained-coarse-grain gradient layer, then control high energy ball beam hit ultra-fine crystal layer be allowed to gradient distribution and with the Ultra-fine Grained at deep thickness-thick
Brilliant gradient layer connects the gradient layer to form continuum one, and last low energy ball beam impact surface is to reduce roughness.The method of the present invention
It is combined by mixing yoghurt with high-speed severe plastic deformation, be suitble in/big thicknesses of metal plate surface prepares millimeter
The high-strength gradient layer of grade thickness.Conventional surface mechanical processing method is solved because prepared Thickness of Gradient Layer is too small, gradient layer knot
Structure level is few, and cannot effectively improve the practical large-thickness component obdurability of engineering, antifatigue damage accumulation, wear Characteristics
Present situation.
Gradient layer at the deep thickness refers to prepare the bottom position of ultra-fine crystal layer in multiple mixing yoghurt, with
To the increase of surface distance, coarse-grain is deformed by the ultra-fine crystal layer of perfect recrystallization, recrystallization Ultra-fine Grained and serious shear plasticity successively
Mixed layer, the gradient-structure layer that is formed of amount of plastic deformation the coarse-grain layer, the original state coarse-grain layer that gradually weaken, and subsequent metal
The accumulating plastic deformation of ball impact can not influence the depth.
After ultra-fine crystal layer prepared by the multiple quickly cooling mixing yoghurt refers to the agitated serious pyroplastic deformation of friction
Uniformly recrystallization, but the homogenous superfine crystal structure layer that can not be grown up under the conditions of quickly cooling is assisted occurs.
After the multiple quickly cooling mixing yoghurt, material is completed the first step and is modified, though intensity has certain promotion, ladder
Degree layer thickness is limited and most surface layer is not up to nanocrystalline structure.
The present invention is achieved through the following technical solutions：
A kind of big thickness is nanocrystalline-preparation method of the surface graded layer of Ultra-fine Grained-coarse-grain, it is more than the metal of 1mm in thickness
On plank, first the ultra-fine crystal layer of grade thickness and Ultra-fine Grained-coarse-grain gradient layer are obtained with multiple quickly cooling mixing yoghurt method；
High energy ball beam is controlled uniformly to hit ultra-fine crystal layer again and obtains nanocrystalline-Ultra-fine Grained gradient layer, the big thickness is nanocrystalline-ultra-fine
The thickness of the surface graded layer of crystalline substance-coarse-grain is more than 1000 μm, and high energy ball refers to a diameter of 0.5-20mm, stroke speed 20-150m/
The kinetic energy ball of s.
The multiple quickly cooling mixing yoghurt method is specially：Metal target plank of the thickness for h ＞ 1mm is selected, is used
Diameter and length are respectively that the mixing needle of d and l carries out multiple equidistant reciprocal displacement mixing yoghurt under the conditions of quickly cooling
Until completing the processing of the entire target area of plate face, the displacement distance of reciprocal displacement mixing yoghurt is u, wherein 1mm every time
＜ l ＜ h, d/2≤u≤d.
The feed speed of multiple quickly cooling mixing yoghurt is 20-800mm/min, and the rotary speed of mixing needle is 100-
3000r/min.Ensure without manufacturing deficiency in the case of mixing yoghurt parameter preferably compared with low_input_power parameter group, that is,
The parameter group of the low rotary speed of high feed speed, purpose are identical with selection quickly cooling condition：The heat for reducing mixing yoghurt is followed
Ring time and peak temperature accelerate to cool down and reduce the annealing after recrystallization and grow up effect.
Quickly cooling condition can be cooled down or be used cooperatively with selective flow water cooling, dry ice cooling, compressed air.
After being hit with high energy ball beam, the surface that gradient layer is uniformly hit with low energy ball beam is further included.Low energy ball refers to directly
The low kinetic energy ball that diameter is 0.1-4mm, stroke speed is 5-150m/s, stroke speed the hitting no more than high energy ball beam of low energy ball beam
Speed is hit, and low energy bulb diameter is less than high energy bulb diameter.
A length of 30s-120min during the shock of high energy ball beam.It is that material surface layer is applied largely that high energy ball beam, which hits purpose,
High-speed accumulating plastic deformation, ultra-fine crystal layer gradient distribution is made in the case where ensureing surface flawless and is connected to agitating friction
Gradient layer at the formed deep thickness of processing forms the gradient-structure layer of continuum one, and most surface layer is refined to nanometer
Crystal structure.High energy ball preferably has the metal steel ball of high-strength tenacity energy or the ball of other materials.In addition it is basic to what is chosen shuttles
It is required that it is that toughness and tenacity is higher than handled material, ordinary circumstance is more stronger better.
A length of 10s-120min during the shock of low energy ball beam.Purpose is to reduce the roughness of material surface.Low energy ball can be with
It is the ball of the metal ball or other materials with high-strength tenacity energy.
Sheet metal also needs to be removed oxide layer processing before multiple quickly cooling mixing yoghurt.
The inventive concept of the present invention is：
For existing surface machinery nanosizing class method, inventor has found that surface Thickness of Gradient Layer is confined to hundreds of microns
Main reason is that：
(1) mechanical load in certain energy range can only be used to handle, excessively high instantaneous energy be easy to cause material table
The defects of surface roughness is excessive or even cracked structure simultaneously loses bearing capacity；
(2) under loading condition, strain rate and accumulated plastic strain amount decay rapidly with the increase of depth in logarithm, and
And the material of before processing is mostly yielding coarse structure, a large amount of dislocations are continued to multiply and can effectively be disappeared in shallower superficial layer
The extraneous high-speed load of consumption, buffering, discharges local stress, and Shock stress Wave cannot influence material at deep thickness and deform.Also
It is to say, is difficult to using existing surface mechanical processing method and by improvement or raising load merely and is ensureing surface quality
While increase considerably gradient deformation layer thickness.
At the same time, although mixing yoghurt can prepare recrystallization ultra-fine grained structure layer in metal material, it should
Method, which develops into, is independent that surface is modified or structural material intensifying method still faces problems with：
(1) under the conditions of no cooling device assists quickly cooling, recrystal grain easy fast growth in stirring area is in coarse-grain, separately
Outside, even process very thin thickness and stringent control quickly cooling process also be difficult to obtain high-strength nanostructured crystal grain, and it is prepared again
The intensity difference deformation states ultra-fine grained structure of crystalline texture is farther out, that is to say, that directly strengthen whole to structure of processing hard layer is imitated
Fruit is very low；
(2) it is difficult to prepare the ultra-fine grained structure of big thickness, because the mixing yoghurt of big thickness needs very high heat defeated
Enter, this is contradicted, and easily formed under low_input_power processing conditions with the requirement that quickly cooling inhibits recrystal grain to grow up
Large-sized hole even crackle, fine copper and copper alloy especially with high thermal conductance；
(3) in addition to factory interface, prepared Ultra-fine Grained region is homogeneous texture, uncoordinated by mechanics in load bearing process
Coupling and intensifying effect caused by unit cooperative transformation is very small.
The present invention is using multiple quickly cooling mixing yoghurt as the first step of big thickness gradient layer preparation process, it is intended to obtain
The ultra-fine crystal layer in surface and follow-up high energy ball beam hit gradient layer at the deep thickness that strain cannot influence.Cooling system is auxiliary
It helps quickly cooling process that can shorten the thermal cycle period, reduce peak temperature, therefore avoids soft in convention stir friction process
The formation and the recrystal grain short annealing of thermoplasticity stirring area of heat affected area are grown up effect.The Ultra-fine Grained formed have etc.
Axis small size is evenly distributed, the feature that transgranular dislocation density is high, brings structure gradient for follow-up high energy ball impact a series of
Benefit：1st, the lattice defects structure such as small-size grains, high density crystal boundary and dislocation has high energy ball beam impact load relatively low
(relative to coarse-grain) absorbs, cushioning effect, and impact stress wave attenuation is slow and can influence at more deep thickness, this is advantageous for shape
It is connected into the surface graded layer of bigger thickness and guarantee with the Ultra-fine Grained at deep thickness-coarse-grain gradient layer；2nd, superficial layer crystal grain
Refinement mechanism is different from coarse grain material, and refining efficiency higher, most surface nanostructured layer thickness is deeper, gradient layer average crystal grain ruler
Very little smaller, integral strength also higher；3rd, evenly, surface roughness is relatively low for intergranular deformation.
Multiple quickly cooling mixing yoghurt parameter or high energy ball beam hit the setting of technological parameter to big thickness gradient layer
Microstructure have a very big impact, general multiple quickly cooling mixing yoghurt parameter or high energy ball beam hit technological parameter
Setting will appear advantageous effects and unfavorable effect, advantageous effects be invention achieves excellent effect, unfavorable effect then has
It is following several：The first be mixing yoghurt heat input it is excessively high crystal grain recrystallization in processing district is caused to grow up, forms heat affected area,
Without gradient transitional lay at deep thickness；Second is very few the defects of internal or surface is caused to form cavity, the crackle structure of heat input；
The third, which is that high energy ball kinetic energy is excessively high, causes face crack or serious roughness；4th kind is that high energy ball energy deficiency causes surface
Nanocrystalline-Ultra-fine Grained gradient layer is excessively thin and cannot be connect with gradient layer at deep thickness.The present invention is by rubbing to the stirring of multiple quickly cooling
The depth, heat input and the innovative of high energy ball impact energy for wiping processing are set, the final big thickness for obtaining zero defect structure
Gradient layer.
A kind of big thickness of the present invention is nanocrystalline-preparation method of the surface graded layer of Ultra-fine Grained-coarse-grain, prepared table
The structure feature of face gradient layer is：It is from outward appearance to inner essence thick in nanocrystalline-deformation states Ultra-fine Grained-recrystallization Ultra-fine Grained-deformation states successively
Brilliant-original state coarse-grain multiple gradients continuous transition, from outward appearance to inner essence hardness continuously decreases the gradient layer, and the thickness of entire gradient layer reaches
To millimeter magnitude and surface and inside all without crackle, hole the defects of structure.So-called deformation states Ultra-fine Grained refers to that recrystallization is super
Fine grain forms the Ultra-fine Grained to nanostructured transitional form after accumulated plastic strain.Deformation states coarse-grain is added in agitating friction
The coarse-grain that coarse-grain not yet recrystallizes after accumulation thermoplastic shear strain during work.
The present invention is based on across scale gradient coupling and intensifying Mechanism Design and prepare and can be used to improve engineering actually big thickness
The big thickness gradient superficial layer of component toughness and tenacity.In process aspect, using the method for stepwise gradient, solves existing surface
By improving the problem of Thickness of Gradient Layer can not be significantly increased in input deformation energy in mechanical method for making Nano.The advantages of its is specific and have
Beneficial effect is as follows：
1. reciprocal multiple mixing yoghurt region is limited without size, large area material, quickly cooling technique energy can be handled
It is effective to ensure that machining area is the ultra-fine grained structure for recrystallizing state, also, the process be in follow-up high-energy metals ball impact
Applied plastic strain is difficult to Ultra-fine Grained-coarse-grain gradient transitional lay that the grade depth touched forms hundreds of microns thickness；
2. the defects of ultra-fine crystal layer that multiple quickly cooling mixing yoghurt is formed, crystal boundary, dislocation, structure accounting was very high, right
There is follow-up high energy ball beam impact load relatively low (relative to coarse-grain) to absorb, cushioning effect, and then advantageously form thicker
Nanocrystalline-Ultra-fine Grained gradient transitional lay, and ensure to be formed continuously unified big thickness gradient layer with the gradient layer at deep thickness；
3. grain size distribution wider range of Ultra-fine Grained prepared by multiple quickly cooling mixing yoghurt, wherein very one big
The size divided is less than the dislocation pack arrangement that severe plastic deformation is formed, and has the refinement different from coarse-grain under high energy ball impact
Mechanism, and refining efficiency higher, the most surface nanocrystalline structure layer thickness formed is deeper, and gradient layer average grain size is more
It is small, integral strength also higher；
4. the control impact energy of low energy metal ball beam effectively reduces the roughness left by preceding step.
5. the gradient layer of big thickness can provide broader migration section in deformation process for mechanics heterogeneous interface prepared by,
The corresponding coupling that can be accumulated between more geometry necessity dislocations and higher long-range internal stress, that is, the heterogeneous unit of mechanics is strong
Change acts on；
6. the excessive interface of the gradient layer at deep thickness left by multiple quickly cooling mixing yoghurt, Ultra-fine Grained and coarse-grain
More sharp, this can provide very strong passivation, inhibition, and then contribute to for Deformation Localizations such as surface layer shear band, crackles
Material homogeneous deformation ability and carrying persistence.
Description of the drawings
Attached drawing described herein is used for providing further understanding the embodiment of the present invention, forms one of the application
Point, do not form the restriction to the embodiment of the present invention.In the accompanying drawings：
Fig. 1 is the agitating friction for preparing big thickness gradient layer in embodiment 1 in Cu-30wt.%Zn with the method for the present invention
Machining sketch chart.
Fig. 2 is with the big thickness gradient layers of Cu-30wt.%Zn prepared by the method for the present invention and conventional surface machine in embodiment 1
The hardness distribution of gradient layer prepared by tool processing method.
Fig. 3 is 25 μm away from surface that the big thickness gradient layers of Cu-30wt.%Zn prepared by the method for the present invention are used in embodiment 1
The nanostructured crystal grain at place.
Fig. 4 is away from 1000 μ of surface in embodiment 1 with the big thickness gradient layers of Cu-30wt.%Zn prepared by the method for the present invention
Recrystallization ultra-fine grained structure at m.
Fig. 5 is away from 1600 μ of surface in embodiment 1 with the big thickness gradient layers of Cu-30wt.%Zn prepared by the method for the present invention
Annealed state coarse-grain at m.
Specific embodiment
To make the objectives, technical solutions, and advantages of the present invention clearer, with reference to embodiment and attached drawing, to this
Invention is described in further detail, and exemplary embodiment of the invention and its explanation are only used for explaining the present invention, do not make
For limitation of the invention.
Embodiment 1
The big thickness of Cu-30wt.%Zn is nanocrystalline-the surface graded layer of Ultra-fine Grained-coarse-grain, specific process approach is as follows：
(1) 6.5 × 100 × 300mm is taken3Cu-30wt.%Zn plates, 650 DEG C of two hours of annealing in vacuum drying oven, removal
Mixing yoghurt equipment style platform is fixed on after surface oxide layer.
(2) multiple cooling rate mixing yoghurt：Selected mixing needle length 1.2mm, diameter 4mm and shaft shoulder diameter 10mm,
Mixing yoghurt rotating speed 1200r/min, feed speed 200mm/min, quickly cooling liquid be low temperature flow, machining path such as Fig. 1 institutes
Show, terminate since the style plate lower left corner and to the lower right corner, A is machining starting point in figure, and B is processes terminal, single machining path
Length for 270mm, end moves to right distance as 3.85mm.Remove indivedual overlaps of finished surface and the seamed edge of junction.Gained
The average grain size of homogenous superfine crystal structure is 580nm in layer, and hardness number 160.5HV is far above the 119.7HV of original CG.
Machined layer bottom, by perfect recrystallization state ultra-fine crystalline region through Ultra-fine Grained with elongate shape severe plastic deformation coarse-grain mixed zone and
Heat engine is plastically deformed the zone of influence to original annealed state CG transition, forms the gradient layer that thickness is about 500 μm.The gradient layer is away from surface
For distance more than 1000 μm, the plastic strain of sequent surface mechanical treatment can not feed through to the depth.
(3) high energy ball beam is hit：The steel ball size of controlled high-energy metals ball beam be 2.4mm, speed 60m/s, speed
Direction is less than 10 ° with plate face normal direction angle theta, and the ultra-fine crystal layer hit prepared by mixing yoghurt uniformly, universal is held
The continuous time is 5min.High energy ball beam is hit, and completes the gradient distribution of ultra-fine crystal layer, and most surface layer undergoes very high strain rate
With accumulation plastic strain, the nanostructured layers of about 60 μ m-thicks are formed, with the increase of thickness, recrystallize the product that Ultra-fine Grained is undergone
Tired plastic strain and strain rate continuously decrease, and form the gradient layer of about 1000 μm of overall thickness.Due to mixing yoghurt parameter
Collocation with high-energy metals ball beam impact parameter selects, and the nanocrystalline-Ultra-fine Grained gradient layer formed can be prepared with step (2)
Deep thickness at Ultra-fine Grained-coarse-grain gradient layer form the entirety of continuum one.
(4) low energy metal ball beam is hit：The purpose of the step is to reduce the roughness on surface handled by step (3), is controlled
The kinetic energy of metal ball beam processed is relatively low, steel ball size 0.5mm, speed 40m/s, directional velocity and plate face normal direction angle theta
Less than 10 °, the duration of uniform, universal shock is 3min.
In order to improve gradient layer proportion, repeatable above-mentioned steps prepare identical gradient in the another side of style plate
Layer.
In Fig. 2 lattice line for above-mentioned steps it is prepared have on two-sided big thickness gradient laminar sample sectional area hardness with
The changing rule of depth, it can be seen that there is a continuous gradient layer of nearly 1500 μm of overall thickness on surface, and of the total volume 44.6%,
Hardness number is gradually down to 119.7HV from the 266.4HV of most surface.Ball line in the figure is using identical with the above process
Material preparation, high energy ball impact, low energy ball impact but without the hardness point of sample in cross section prepared by mixing yoghurt step
Butut, it can be seen that about only 750 μm, hardness reduces rapidly the surface graded layer thickness of the sample from the 258.2HV of most surface
To the hardness for moving back state coarse-grain, only about 22 μm, and surface roughness is relatively large of the nanostructured layers of most surface.
Material prepared surface does not have the defects of crackle structure.Fig. 3, Fig. 4 and Fig. 5 are big thickness ladders prepared by the above process
Layer is spent away from the microsctructural photograph at the different distance of surface：Fig. 3 is the transmission bright field image of the nanocrystalline structure at 25 μm away from surface,
Statistical average crystallite dimension only 17nm, relatively large sized crystal grain is interior to have a large amount of twin structures；Fig. 4 is 1000 μm away from surface
By the agitating friction thermoplasticity processing ultra-fine grained structure that quickly cooling is formed after recrystallization, crystal grain is uniformly isometric and equally contains big at place
Measure twin；Fig. 4 is the coarse-grain metallograph of full annealing state at 1600 μm of surface, about 38 μm of average grain size.
It is tested through quasi-static tensile, the entirety of the prepared 6.5mm Cu-30wt.%Zn plates with big thickness gradient layer is bent
Intensity is taken as 302.8MPa, far above the 102.2MPa of pure coarse-grain state；And uniform elongation can adhere to 33.4%.
To further illustrate, the present invention is relative to the usefulness of the prior art, and inventor is using 6.5mm Cu-
30wt.%Zn plates have done relevant comparative's experiment.It is as follows to test a content：Comparative example 1 (processing of tradition machinery nanosizing)：High energy ball
Shock+low energy ball impact；Comparative example 2 (only mixing yoghurt modification)：Quickly cooling mixing yoghurt；Comparative example 3：No quickly cooling is stirred
Mix friction processing+high energy ball impact+low energy ball impact, comparative example 4：Cold mixing yoghurt+high energy the ball impact of liquid nitrogen hypervelocity+low
Energy ball impact, the relevant parameter that wherein comparative example 1-3 occurs corresponding parameter related to embodiment 1 is identical, the speed of comparative example 4
Cold mixing yoghurt is cold worked for hypervelocity, remaining parameter and embodiment 1 are identical.It is as follows to test two contents：Identical multiple speed
Cold mixing yoghurt+difference kinetic energy high energy ball impact, multiple quickly cooling mixing yoghurt condition, parameter and the implementation of the experiment
Example 1 is identical.
The result such as table 1 of experiment one：
Table 1
The results are shown in Table 2 for experiment two：
Table 2
As can be seen that the big thickness gradient layer prepared by the method for the present invention is in, big Thickness Engineering structural material has
Extraordinary Strengthening and Toughening effect, the wherein coupling interaction between the heterogeneous unit of gradient layer mechanics can contribute additional in deformation process
Strengthen and processing hardening, center portion coarse-grain layer can be released effectively its stress concentration to the effect of contraction on surface layer and inhibit its strain rate effect
Localization trend makes overall structure maintain homogeneous deformation.
Embodiment 2：
With big thickness it is nanocrystalline-the pure Cu of the surface graded layer of Ultra-fine Grained-coarse-grain.
The agglomerate body fine copper for having both high conductivity and surface wear resistance has by force in military project weaponry field
Strong demand.As this potential method is solved the problems, such as, the wear Characteristics of material prepared are typically restricted to making Nano surface
The smaller surface graded layer of thickness.This case prepares thickness up to the ladder of millimeter magnitude using the method for the present invention on thick pure Cu plates
Spend layer.
The present embodiment and embodiment 1 in preparation process difference lies in：
(1) original material selected by is the pure Cu plates of 8mm thickness；
(2) feed speed of quickly cooling mixing yoghurt is 60mm/min, and mixing needle rotating speed is 800r/min.
(3) speed that high-energy metals ball beam is hit is 50m/s, and the duration stagnates for 8min and intermediate once 10min
Interval, the purpose for stagnating interval be prevent because hit the duration it is long cause style temperature excessively high due to deformation layer crystal grain reply
Even grow up；
(4) low energy metal ball stroke speed is 30m/s.
Other processes and parameter are identical with embodiment 1.The defects of material prepared surface flawless, gradient layer connect
Continuous and overall thickness reaches 1350 μm of gradient layer, hits 700 μm of formed gradients much thicker than individually high and low energy metal ball beam
Layer.But the pure big thickness gradient layers of Cu are relatively thin with respect to embodiment 1, the reason is that the heat engine zone of influence of pure Cu mixing yoghurts is relatively thin,
Bottom formed in only 350 μm of region for crystallizing ultra-fine crystal orientation annealed state coarse-grain transition.The thickness of most surface nano-crystalline layers is about
42μm。
The above method is not limited to the copper-zinc alloy being previously mentioned and fine copper metal material, can also be aluminium, nickel, titanium, steel and
The metal materials such as its alloy.
For the advantageous effect further illustrated the present invention, the present invention has also carried out the pure titanium of 301L stainless steels, technique, 1050 works
It is prepared by the big thickness gradient layer of industry fine aluminium.Specific experiment technique and result such as the following table 3：
Table 3
Above-mentioned experiment case study is compared to can be seen that for specific material, only suitable quickly cooling mixing yoghurt heat
Input condition is arranged in pairs or groups the high energy ball impact of appropriate kinetic energy, can just prepare surface and it is internal all without defect, gradient layer is continuous, tool
There is the big thickness gradient layer of high-strength tenacity energy.
Above-described specific embodiment has carried out the purpose of the present invention, technical solution and advantageous effect further
It is described in detail, it should be understood that the foregoing is merely the specific embodiment of the present invention, is not intended to limit the present invention
Protection domain, all within the spirits and principles of the present invention, any modification, equivalent substitution, improvement and etc. done should all include
Within protection scope of the present invention.
Claims (6)
1. a kind of big thickness is nanocrystalline-preparation method of the surface graded layer of Ultra-fine Grained-coarse-grain, which is characterized in that including following several
A step：
On sheet metal of the thickness more than 1mm, first the super of grade thickness is obtained with multiple quickly cooling mixing yoghurt method
Thin crystal layer and Ultra-fine Grained-coarse-grain gradient layer；
Uniformly hit ultra-fine crystal layer with high energy ball beam again and obtain nanocrystalline-Ultra-fine Grained gradient layer, finally obtain big thickness it is nanocrystalline-
The surface graded layer of Ultra-fine Grained-coarse-grain, the big thickness is nanocrystalline-and the thickness of the surface graded layer of Ultra-fine Grained-coarse-grain is more than 1000 μm,
High energy ball beam refers to the kinetic energy ball beam that stroke speed is 20-150m/s, and the multiple quickly cooling mixing yoghurt method is specific
For：Select thickness forhThe metal target plank of ＞ 1mm is respectively with diameter and lengthdWithlMixing needle under the conditions of quickly cooling
Equidistant reciprocal displacement mixing yoghurt is carried out repeatedly until completing the processing of the entire target area of plate face, it is reciprocal every time to move
The displacement distance of position mixing yoghurt is u, wherein 1mm ＜l＜ h, d/2≤u≤d, it is reciprocal every time to shift mixing yoghurt
Feed speed for 20-800mm/min, the rotary speed of mixing needle is 100-3000r/min.
2. preparation method according to claim 1, which is characterized in that after being hit with high energy ball beam, further include and use low energy
Ball beam uniformly hit big thickness it is nanocrystalline-surface of the surface graded layer of Ultra-fine Grained-coarse-grain.
3. preparation method according to claim 2, which is characterized in that low energy ball beam refers to that stroke speed is 5-150m/s's
Low kinetic energy ball beam, the stroke speed of low energy ball beam is not more than the stroke speed of high energy ball beam, and low energy bulb diameter is less than high energy ball
Diameter, the high energy bulb diameter of high energy ball beam is 0.5-20mm, and the low energy bulb diameter of low energy ball beam is 0.1-4mm.
4. preparation method according to claim 1, which is characterized in that a length of 30s-120min during the shock of high energy ball beam.
5. preparation method according to claim 2, which is characterized in that a length of 10s-120min during the shock of low energy ball beam.
6. according to the nanocrystalline-Ultra-fine Grained-coarse-grain surface ladder of big thickness that claim 1-5 any one of them preparation methods obtain
Spend layer, which is characterized in that structure feature is：It is in from outward appearance to inner essence nanocrystalline-deformation states Ultra-fine Grained-recrystallization Ultra-fine Grained-change successively
Form coarse-grain-original state coarse-grain multiple gradients continuous transition, big thickness is nanocrystalline-thickness of the surface graded layer of Ultra-fine Grained-coarse-grain
The defects of for grade and surface and internal flawless or hole structure.
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| CN102304679A (en) * | 2011-09-28 | 2012-01-04 | 宋玉军 | Amorphous nanocrystal gradient functional material and preparation method thereof |
| CN103121145A (en) * | 2013-02-07 | 2013-05-29 | 沈阳航空航天大学 | Method for manufacturing ultra-fine grain/nanocrystalline board and based on ultrasonic wave assistance semi-solid state stirring friction processing technology |
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| CN102304679A (en) * | 2011-09-28 | 2012-01-04 | 宋玉军 | Amorphous nanocrystal gradient functional material and preparation method thereof |
| CN103121145A (en) * | 2013-02-07 | 2013-05-29 | 沈阳航空航天大学 | Method for manufacturing ultra-fine grain/nanocrystalline board and based on ultrasonic wave assistance semi-solid state stirring friction processing technology |
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