Realize the high-speed processing method of superfine crystal grain structure on the metallic substance top layer
Technical field
The present invention relates to the treatment process that the metal material surface of nanostructure is out of shape at a high speed, a kind of high-speed processing method of realizing superfine crystal grain structure on the metallic substance top layer is provided especially, has formed the superfine crystal grain structure of nano-scale, submicron-scale on the metallic substance top layer.
Background technology
Single-phase or the heterogeneous crystalline material that nano material is made up of less than the substructure of 100nm scantlings of the structure, because the nano material crystal boundary occupies very big ratio, nano material has the excellent properties that is different from and usually is superior to common polycrystalline material usually, high strength for example, high spread coefficient, performances such as good electricity, magnetics.
At present, the research in nano structural material field is primarily aimed at the aspects such as synthetic, preparation, constitutional features, thermostability of block nanometer structured material.From existent method, methods such as vapor condensation, mechanical ball milling are difficult to eliminate the hole in the prepared material, the detrimentally affect of defectives such as pollution; And wait passage extruding (ECAP), laminated rolling to engage the shortcoming that severe plastic deformation methods such as (ARB) has remedied preceding method, but equipment loss is big, inefficiency, cost height; Its shape of material, the size handled all have significant limitation, are difficult to realize industrial application.
In fact, the inefficacy of material occurs in the surface of material mostly, so the quality of material surface structure properties directly influences the integrated performance index of engineering metal material.Conventional engineering material upper layer microtexture size is refined to nanometer, submicron-scale, utilize the excellent properties of nano structural material to improve structure, the performance of material surface, especially fatigue property, corrosive nature and friction, polishing machine etc., thereby the over-all properties and the military service behavior that improve engineering materials.
The method that existing metal material surface is handled mainly contains: (1) top coat.Utilize methods such as coating and deposition technique such as PVD, CVD, sputter coating, plating to generate one deck nanostructured layers at substrate material surface.The key of this technology is between coating and the matrix and the bonding force between the coating particle, the easiest also the inefficacy of normal generation be peeling off of coating or come off.In addition, facility investment is bigger, and production cost is higher, and the engineering metal material surface that is not suitable for enormous amount is handled; (2) surperficial mechanical treatment process.Utilize the surface mechanical attrition treatment technology, under the repeat function of plus load, the intense plastic strain that the open grain structure of material surface produces through different directions and gradually fragmentation to nanometer scale.Yet the sample surfaces roughness that present this treatment technology obtains is bigger, can't satisfy requirement of actual application, has limited its popularization in industry, and the sample shape of processing also has significant limitation.In addition, schedule of operation is more loaded down with trivial details, and the pallet and the consumption of ball ball of grinding use are big, causes cost to increase.
Summary of the invention
The object of the present invention is to provide a kind of new metallic material surface high speed deformation processing method, its less investment, simple to operate, industrial being easy to realized, with nanometer, the submicrometer structure layer difficult drop-off of its preparation, and can come the workpiece of deal with complex shapes, guarantee lower surfaceness simultaneously by controlling various conditions, can also use the mechanical workout cooling technology of comparative maturity, thereby provide possibility for the surface property that comprehensively improves the engineering metal material.
Technical scheme of the present invention is:
The invention provides a kind of metal material surface high speed deformation processing method, this treatment process device is by the Work piece high-speed running gear, and tool feeding mechanism and cooling body are formed.The present invention adopts the cutter of certain curvature radius to do axial feed motion, and processed workpiece is done high speed rotary motion, the temperature of metal material surface when selecting different heat-eliminating mediums to cool off to control to handle.Wherein, the radius-of-curvature preferable range of cutter is 4mm---8mm; The axial feed velocity preferable range of cutter is 150mm/min---250mm/min; Processed workpiece rotating speed preferable range is 600rpm---1000rpm; The metal material surface temperature preferable range of processed workpiece is-100 ℃---20 ℃; Heat-eliminating medium can be high-pressure oil mist, liquid nitrogen gas.
The principle of institute of the present invention foundation is to cause metal material surface to produce severe plastic deformation by distortion at a high speed, make surface microstructure by dislocation multiplication, move, bury in oblivion, process such as rearrangement is refined to nano-scale.Thereby any equipment that makes cutter and workpiece present the high speed relative movement all can be used as structure of the present invention, as various lathes, grinding machine etc.
Utilize the high speed deformation technology, workpiece surface carried out repeatedly deformation process of low temperature, processing parameter:
Deformation strain speed: 10
3-10
6s
-1
The deformation strain amount: total deformation greater than 2.9 (method of calculation:
ε is a deflection, and γ is tangential strain);
Texturing temperature :-196 ℃---100 ℃.
The present invention has following advantage:
1. treatment process is simple.The present invention utilizes the high speed deformation technology, and treatment process is simple, is easy to control well processing parameters and texturing temperature.Present traditional cutting technology is carried out necessary improvement, optimize processing parameter and texturing temperature, can obtain surperficial refinement structural sheet.
2. suitability is strong.Be applicable to the surface treatment of various complex parts, and be under the situation of the chemical ingredients that does not change material, only come reinforced metal and alloy by the microtexture of adjusting material.
3. handle rear surface quality height.The processing mode of present method has guaranteed whole surface-treated homogeneity, thereby obtains lower surfaceness, and deformation layer thickness increases, and is easy to after finishing dealing with by the industrial means of various routines the surface be repaired.
The present invention carries out the high speed deformation process by the surface to metallic substance, forms certain thickness nanometer, submicron weave construction at material surface, and keeps the top layer and the whole components unchanged of material.Grain size distribution:, be the texture of coarse crystal of refined structure, Deformation structure's layer and the matrix of nanometer, submicron-scale in the top layer certain thickness (thickness is approximately 20 μ m---300 μ m) along depth direction.Because the destruction of material is originated from the surface of material, so the optimization of surface tissue helps the raising of material fundamental property, and as suppressing aspect the crack growth, small grains is better than coarse grain.Otherwise aspect the resistance crack propagation, coarse grain is better than small grains.Like this, the desirable combination of small grains top layer and coarse grain matrix is more favourable to the work-ing life that prolongs material.In a word, the present invention combines the excellent properties of nano material with the engineering metal material, gives property for traditional metallic substance, and this all has very wide prospect in fundamental research and engineering application facet.
Description of drawings
Fig. 1 is the pure copper material top layer transmission electron microscope photo (speed of mainshaft: 600rpm) of utilizing the technology of the present invention to handle.
Fig. 2 is the top layer transmission electron microscope photo (speed of mainshaft: 1000rpm) of utilizing the pure copper material of the technology of the present invention processing.
Fig. 3 (a)-(c) is the top layer transmission electron microscope bright (a) that utilizes the pure copper material of the technology of the present invention processing, dark (b) picture, diffraction (c) photo (speed of mainshaft: 600rpm).
Fig. 4 is adopted the apparatus structure synoptic diagram by treatment process of the present invention.Among the figure, 1 piece-holder and rotating mechanism; 2 cutter clamping and feed mechanisms; 3 mist of oil cooling jets; 4 heat-eliminating mediums; 5 workpiece; 6 cutters.
Embodiment
As shown in Figure 4, device that treatment process of the present invention adopts is by piece-holder and rotating mechanism 1, cutter clamping and feed mechanism 2, mist of oil cooling jet 3, heat-eliminating medium 4, workpiece 5, cutter 6 is formed, its working process is as follows: the present invention adopts the cutter 6 of certain curvature radius, under the drive of cutter clamping and feed mechanism 2, do axial feed motion, processed workpiece 5 is done high speed rotary motion under the drive of piece-holder and rotating mechanism 1, the temperature of metal material surface when selecting different heat-eliminating mediums to cool off to control to handle, the high pressure mist of oil (oil-injection machine air feed air pressure is greater than 80psi) of cooling jet 3 ejections, and cooled with liquid nitrogen gas is as heat-eliminating medium 4.Wherein, the radius-of-curvature preferable range of cutter is 4mm---8mm; The axial feed velocity preferable range of cutter is 150mm/min---250mm/min; Processed workpiece rotating speed preferable range is 600rpm---1000rpm; The metal material surface temperature preferable range of processed workpiece is-100 ℃---20 ℃.
Below by embodiment in detail the present invention is described in detail.
Embodiment 1
Utilize surperficial high speed deformation technology to handle pure copper material:
Equipment: surperficial high speed deformation process equipment;
The speed of mainshaft: 600rpm;
Deformation strain speed: 10
3-10
4s
-1
Deformation strain amount: 3-5;
Texturing temperature: 20 ℃;
Handle passage: 8;
Pure copper material: purity 99.97% (weight percent), through 600 ℃ of annealing 3 hours, grain-size 20 μ m.
Processing obtains the pure copper material of top layer refinement, and as Fig. 1, skin depth is about 60 μ m, and its microtexture principal character is that minor axis dimension is 164nm near equiaxial sub-micron grain/subgrain, and major axis dimension is 351nm.
Embodiment 2
Utilize surperficial high speed deformation technology to handle pure copper material:
Equipment: surperficial high speed deformation process equipment;
The speed of mainshaft: 1000rpm;
Deformation strain speed: 10
3-10
4s
-1
Deformation strain amount: 3-5;
Texturing temperature: 20 ℃;
Handle passage: 8;
Pure copper material: purity 99.97%, through 600 ℃ of annealing 3 hours, grain-size 20 μ m.
The surface structure that processing obtains such as Fig. 2, skin depth are about 30 μ m, and minor axis dimension is 178nm, and major axis dimension is 587nm.
Embodiment 3
Utilize surperficial high speed deformation technology to handle pure copper material:
Equipment: surperficial high speed deformation process equipment;
The speed of mainshaft: 600rpm;
Deformation strain speed: 10
3-10
4s
-1
Deformation strain amount: 3-5;
Texturing temperature: 20 ℃;
Handle passage: 6;
Pure copper material: purity 99.97%, through 600 ℃ of annealing 3 hours, grain-size 20 μ m.
The skin depth that processing obtains is about 30 μ m, and minor axis dimension is 158nm, and major axis dimension is 604nm.
Embodiment 4
Utilize surperficial high speed deformation technology to handle pure copper material:
Equipment: surperficial high speed deformation process equipment;
The speed of mainshaft: 600rpm;
Deformation strain speed: 10
3-10
4s
-1
Deformation strain amount: 3-5;
Texturing temperature :-100 ℃;
Handle passage: 6;
Pure copper material: purity 99.97%, through 600 ℃ of annealing 3 hours, grain-size 20 μ m.
The top layer that processing obtains is near equiaxial nanocrystalline, the crystal grain minor axis dimension is 19nm in the top layer 5 μ m, major axis dimension is 38nm, nanometer layer thickness is about 20 μ m, shown in Fig. 3 (a)-(c), utilize the top layer transmission electron microscope of the pure copper material that the technology of the present invention handles bright, dark field image, diffraction photo.
Comparative example 1
Lamellar spacing Deng fine copper after passage extruding (ECAP) processing 8 passages is 290 ± 160nm, method of the present invention and this method fundamental difference are that present method has adopted low temperature high strain rate deformation technology, can make fine copper surface layer grain size be reduced to nano-scale.
Comparative example 2
Average crystal grain/dislocation born of the same parents that the surface mechanical attrition of fine copper is handled top layer after 5 minutes are of a size of 160nm.The superiority of method apparent surface's mechanical mill treatment process of the present invention is: more even and surfaceness obviously reduces along the surface direction microtexture.