High temperature alloy solders contact trends drawing is out of shape rupture behavior

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In the applied circumstance of high temperature alloy, soldering is important production process, solder quality is in whole solder there is conclusive effect in the structure. Need to bear in use process hand in change the weldment of high temperature alloy of load, still must undertake fatigue school nucleus. Former drawing can is opposite of material microcosmic destroy a process to undertake real time dynamic observation, with take from identical solder the sample of contact exhaustion test specimen undertakes former a drawing, the trends that knows welding line ruptures behavior, undertake comparative with fatigue test result, conduce to improve the knowledge that to soldering contact exhaustion destroys a process, seek improvement to solder thereby the efficient way of quality. 1 test data and data of experiment means test are homebred GH3030 and alloy of GH150 high temperature. Solder sample preparation: ? "Afore-mentioned alloy that Xi holds the post of? Mm board, use solder of arc of argon of automatic butt joint to solder, welding wire is GH3128, the diameter is 1.

6 ~ 2.

5mm, tungsten pole diameter 2.

0 ~ 2.

5mm, solder electric current 70 ~ 90 A, 12 V of electric arc voltage, argon throughput 12 ~ 15 L /min, via X light flaw detection examines after solder. Solder in what experiment without exhaustion the intercept on sample former a drawing sample, in perpendicular cut with line cut at the direction of welding line take former a drawing sample, welding line lies sample is mid, if pursue,1 is shown. Sample is made the same score via grinding, bosseyed polish is spent gently corrode, so that observe constituent drawing,be out of shape process. Dynamic drawing undertakes on the stage of accessory SM-TS40 special drawing in JXA-840 scanning electron microscope, its are the biggest drawing load is 2kN, demarcate of thrust augmentation sensor is 150mV, voltage and load show slope to be the line sexual relationship of 1. Distance of the biggest drawing is 20mm, drawing rate is adjustable, the biggest amount to 50mm/min. In dynamic drawing, can use X ray at the same time can chart appearance (EDS) undertakes ultimate analysis to observation dot. Solder the fatigue experiment of contact sample experiments in exhaustion of hydraulic pressure servo undertake on machine EHF-EG250KN-40L, fatigue load uses axial to pull - pull stress control, sine wave is pulsatile to load, f=4.

5Hz, r=0.

1. Record circular time, the happening that checks fatigue fracture place. 2.

1 solder contact former the macroscopical form appearance of a drawing pursues 2 to solder contact former the macroscopical form appearance of a drawing later period. Welding line is caky below blame balance position casting appearance organization, along with match solder the difference of the scale of material, chemical composition after mixing with mother capable person and cooling condition, the organization is very complex. If the graph is shown 2 times, former a drawing process is medium, when occurrence neck shrinks, welding line office appears to be out of shape apparently inhomogenous sex. This is by solder contact is microcosmic organize inhomogenous sex and complexity to cause. Explain sample is after to load, welding line is in microcosmic organization to be in be out of shape in the process, different to grain organization and its are in-house motion brings about a fault sample correspondence place organizes the local stress that continues to be out of shape place wants to bring to bear on to agree very much, solder so joint appears welding line central expand, form the phenomenon that neck of two paragraphs of type shrinks, neck of sample of accord with plywood shrinks the smallest meet an emergency that abide by can method principle. Metallographic examination discovers test specimen welding line basically is branch brilliant organization. Research shows crystallization forward position has fine branch the alloy of caky interface, its endurance can be optimal, this kind of organization makes treatment sclerosis, deferred a neck to shrink time. Mother capable person is fine organization of brilliant waiting for an axis. Bond organization is more complex, the brilliant waiting for an axis that differs with size with GH150 material boundary is given priority to, with GH3030 material boundary with columnar brilliant is given priority to. Hot influence area has local grain thick change, because high temperature alloy is not had,transform with element different compose. Soldering in the process, eliminate welding line outside caky organization, show because of overheat with the intermediate zone of mother capable person irregular grown. Such, solder microcosmic organization existence wears the whole of contact the organization of each different of 3 kinds of orientaton. Consequently contact is existing to compare serious microcosmic organization inhomogenous sex, they affect joint necessarily be out of shape behavior. Polycrystal when each grain is out of shape cooperating each other is metabolic of material resistance plasticity main form, be in extremely easily otherwise local and premature craze. Afore-mentioned organizations are inhomogenous the gender makes easily solder the difference that contact causes concentration of in-house and microcosmic stress and rate of each grain meet an emergency in process of fatigue function experiment, fatigue crackle will be produced finally in weaker position. 2.

2 former of a sample in drawing microcosmic be out of shape the process pursues 3 showed in surface of the sample in drawing process microcosmic be out of shape circumstance. Undertake along with drawing, what exist inside grain getting power is many below a fault, layer fault action in stress, fault general actuate, form the skid wire of mutual parallel, if pursue,3a place is shown. Plasticity is out of shape must consider to load rate, as a result of former a drawing deformation rate is inferior, grain deformation is evener, slippage takes size of flat, span to agree basically. But the slippage tape that this graph showed a way only, the specification is in even deformation phase, only the slippage department of a direction takes dominant place, this phase alloy will appear initiative sclerosis. Undertake as drawing, the slippage area that can see different way in other grain appears, form aiguille shape or triangle. Learn theory according to crystal, <111> brilliant face is the slide surface of austenite, also be layer fault forms a surface. This brilliant face has 4 basic orientaton, the computation of included angle theory between every brilliant face is 70 ° 32 ′ . If some grain is sectional with <111> parallel or approximate parallel, because the included angle between the fiducial vector of direction of on <111> face 3 slippage is 60 ° , be triangle, so feature of the skid wire inside brilliant accords with the austenite when drawing crystal learns to the relation. Increase as deflection, slippage belt will broaden gradually, appear bend. As a result of every grain to different, the way that the slippage that is not every grain ties with most be helpful for metabolic direction agreeing, cause each grain deformation to have difference. As meet an emergency the quantity increases, grain begins what obedient stress condition falls to be turned round in coordination, be out of shape aggravate, occurrence float protruding. Happen from the original individual grain that has a few area only turn round, to finally almost every grain all produced twist, all the more of exterior float protruding is apparent, if graph 3b place is shown, below the action of tensile stress, the grain of welding line bond is spun apparently, appear preferred orientaton. And grain of area of hot influence of its upper part already appeared skid wire is thick change, bend. Change of appearance of this kind of microcosmic form can explain the inhomogenous sex of macroscopical deformation in certain level. At the same time discovery falls in tensile stress action, the brittleness inside brilliant grain of the 2nd photograph (the grain in the graph changes titanium for nitrogen) with matrix come away, and disintegrate, see graph 3a. The slippage of grain of this kind of the 2nd photograph is little, easy below adscititious stress fragile crack or rupture along border become crackle source, but the deformation aggrandizement ability that also is helpful for improving data sometimes. Inhomogenous organization is like crystal boundary, field trash to wait, also will be opposite solder of contact cut generation influence. From the graph 4 visible crystal boundary and field trash fall in tensile stress action right microcosmic rupture the influence of the mechanism. See by graph 4a, welding line crystal boundary falls in not old stress standard, produce craze at field trash first, but the influence that still cannot judge crystal boundary precipitate. What graph 4b shows is the crackle cause that field trash causes, x ray can chart analysis shows, this kind of field trash basically is the compound of aluminium, titanium or niobium. Former drawing shows extent of field trash Cong Jing or fall off in matrix. Because the stress of field trash be caused by is centered, in hole all round, will form perpendicular at drawing direction show micro-crack. See from this, in pull down stress effect, field trash reachs the weak point that the organization is welding line all round its. 2.

Of 3 crackle produce welding line of high temperature alloy to have good obdurability to cooperate, when sample happening the neck shrinks after the phenomenon, because board shape small sample cannot be caused in ply direction,be out of shape tie, reason cannot form state of planar meet an emergency, initiative crackle can observe directly in sample polish surface. Once the surface forms crackle, criterion near crackle front of area be out of shape also do not accept an obligation basically, can be out of shape freely, show succumb completely condition. Below the action of outside force, crackle front is out of shape as a result of plasticity and edge sample ply is inclined to show with two side stretch shape to tear off, what issue laminose drawing sample with planar stress condition is macroscopical rupture behavior is consistent. Graph different position is in 5 indication sample former the microcosmic form appearance that rupture and mechanism happen in drawing. If graph 5a place is shown, in heartland of board shape sample, skid wire is thick change, curve; grain heel, because be planar stress condition,present; of exterior float protruding, crackle is shown slip model. And sharp edge handles sample stress state of affairs is intricate, easy cause stress concentration, a few model change to produce deformation aggrandizement namely, make farther plasticity is out of shape suffocate suffocate, the result forms apparent brittleness to wear brilliant to rupture in sample brim, the grain that spins from its and exterior skid wire see its early days ever had experienced plasticity to be out of shape. 2.

4 advocate what crackle expands is former what F of graph 6a ~ gives priority to an observation to crackle is produced and expand is former an observation result. Of different orientaton grain be out of shape ability is mixed be out of shape fighting force is to differ, below drawing load, be in necessarily orientaton most the grain that is helpful for slippage and microcosmic internal stress be being centered the most easily begins first, the tissue heals inhomogenous, metabolic of this kind of initiative plasticity is highlighted more optionally. Metabolic grain deflection is worth in the van certainly more than, can produce initiative crackle. If graph 6a place is shown, in one slippage triangle most advanced twist with twin crystal boundary break floor, as a result of deformation aggrandizement, stuff becomes fragile, generation one empty, form advocate the generation with crackle source empty; , make stress condition bate is shown like graph 6b place, empty be spun in direction getting power, tear off along crystal boundary towards the left, after crossing twin crystal boundary, arise again one secondary 6c of graph of crackle source; shows twin brilliant is pulled, crackle is perpendicular slip more easily at the part of drawing direction, advocate crackle inside arises again one secondary 6d of crackle; graph shows new crackle source appears ceaselessly, advocate crackle already connected; graph 6e shows former point of observation takes; of grain of one the 2nd photograph advocate crackle face is local nest having pliable but strong is formed, appear at the same time new empty, advocate the left forward position of crackle, side of towards the left is torn apart quickly, enter the crackle form appearance before 6f of graph of; of full-scale beat a precipitate retreat ruptures finally for sample. Is whole process: ? ? of abb of saline garden green is mutual and concatenate, form advocate crackle; advocate slippage of crackle syncline upper part is stretched, tear off a face to go up grain of slippage of visible move with the body on the ground and; of nest of small pliable but strong are stretched along with crackle, belt of the 2nd photograph gives different quality, break away from matrix or disintegrate; crackle transverse and patulous as a result ruptures finally, its fracture surface is shown cut account completely, without radiative area, cut off for what cause below typical planar stress condition model fracture surface. 2.

Test result watch shows 5 exhaustion 1 times to solder for two groups result of contact exhaustion test, every groups contain 6 data, s is increment standard deviation. Test result makes clear, solder of arc of argon of automatic butt joint solders the fatigue performance of high temperature alloy is good, the data uniformity below low stress level relatively actor. Fatigue fracture surface checks discovery, fatigue crackle source only then be in at solder foot or solder root, discover fatigue cause at the same time above all as microcosmic as welding line surface quality is concerned, just be welding line next microcosmic organization configuration and structure. A discovery when fatigue function is received in solder of arc of argon of butt joint of alloy of test high temperature, its exhaustion life is far the smooth sample under corresponding alloy, and fatigue source arises entirely soldering the bond of contact, then fatigue crackle is patulous bring about contact exhaustion invalidation. By former drawing observation reachs solder contact is microcosmic each area organizes constituent complexity and connect distributinging characteristic, show exhaustion destroys a process to be different from static drawing, material is being handed in change below bear, compare with dead load photograph, in-house slippage is inhomogenous the gender will be bigger. Research makes clear even if same metal organization, be out of shape in different plasticity on the foundation, also can bring about the deformation aggrandizement of different level. High temperature alloy solders the apparent organization inside the bond of contact is inhomogenous of crackle of exhaustion of condition general aggravate produce, such, this area will become the position with relatively weak performance of exhaustion of this kinds of connect. Discover high temperature alloy solders in application structural destruction often is given priority to with low week exhaustion. At present general report crackle often happens at soldering the solder foot place of contact, its are main the reason is to solder the macroscopical and leftover tensile stress of contact and the effect that stress focuses. But in abrasion solder foot former a discovery in tensile test, sample often also breaks the bond that relies on alloy of weaker one party within welding line inside. In different solder the discovery in the examination of fatigue fracture surface below condition, the inchoate deformation sclerosis of blemish of be mingled with of broken bits of common Yu Rong, surface and bond handles fatigue source, this and solder contact former a result that the observation in drawing reachs is consistent. High temperature alloy solders in the process, in multivariate the metal diffuses below not quite sufficient general condition, form the brittleness photograph of the compound between the metal easily in position of welding line bond, and bring about welding line to be changed infirmly. Accordingly improvement solders quality, especially exterior quality is very important, be helpful for reducing the adverse effect of solder foot. 3 conclusion   (sample of 1) board shape former drawing shows high temperature alloy is fused solder strong plasticity of static drawing of place of contact welding line is good, meet an emergency is amounted to 17.

5% , welding line is mid have apparent deformation aggrandizement effect. Sample ruptures closely related form appearance and stress condition, below planar stress condition, crackle forms the blemish inside Yu Jing and crystal boundary to hand in collect place, destroy with ductility give priority to, be in place of sample edges and corners, joint action brings about the complex stress position that creates centrally by stress and treatment sclerosis brittleness ruptures. (Of capable person of mother of alloy of 2) different high temperature fused solder in contact, put in two different bond, in former a discovery in tensile test welding line has inhomogenous neck to shrink phenomenon, among them the tensile strength with GH3030 bond is weaker, it is contact the position with mechanical weaker performance. (Alloy of 3) high temperature is fused solder the microcosmic organization that contact interior exists is inhomogenous quality, be in especially bond, its are microcosmic the organization is inhomogenous reaching among them crystal boundary field trash is to make this kinds of connect fatigue the position that function changes infirmly, will make contact is in fatigue experiment process concentration of stress of Yizhi of as joint as solder foot action and sclerosis of meet an emergency, cause fatigue crackle thereby. CNC Milling