Alloy composition to containing rhenium high temperature of alloy of nickel radical single crystal is abiding reach rupture the influence of function

0wt% low cost alloy of the 2nd acting single crystal. Composition of alloy of high temperature of keyword single crystal is abiding Lao RilingLi Jiarong(Institute Of Aeronautical Materials of 　 of Liu Rongmin of 　 of Gui Zhonglou of 　 of Zhong Zhengang of 　 of creep rupture Effects Of Composition On High Temperature Rupture And Fracture Feature Of Re-containing Ni-based Single Crystal SuperalloysWei Pengyi, beijing) 　 　 [Abstract] 　 A New Secondary Generation Ni-based Single Crystal Superalloy Containing Only 2wt%Re Was Developed.

Effects Of Main Alloying Elements, w, re, ta, al, RE, 1100 ℃ of ～ of On High Temperatures(980) Rupture Properties And Fracture Surface Characteristics Of Re-containing Ni-based Single Crystal Superalloys Were Investigated To Explore The Principle For Improving Alloying And Understand The Fracture Behavior In This Series Of Alloy.

It Is Found That: Increasing The Contents Of Re, w, nb, ta, al, RE, to Certain Extent Will Contribute To Improvement Of High Temperature Rupture Properties, and Then It Is Turned Out To Be Reasonable To Decrease The Necessary Re Contents By Matching Of Contents Of Elements Other Than Re, especially Minor Addition Of RE.

′ of γ of Those Results Are Due To Inpidual And Mutual Effect On Strengthening And Volume Fraction Of Alloy Phases(, γ ) Phase During Creep Process of ′ of γ of And Coarsening Dynamics Of.

　 of Fracture of 　 of Creep Rupture of 　 of Content of 　 of Keywords 　 Single Crystal Superalloy contains rhenium alloy of nickel radical single crystal with its advantageous high temperature is abiding and fight the function such as creep, already lighted the motivation such as gas dynamo in advanced aviation engine, ground get applied extensively in device [1 ～ 3] . Rhenium is changed to the alloy of single crystal alloy although action is remarkable, but our country rhenium is very rare expensive, study rhenium alloy changes mechanism deep consequently, use low cost alloying element to the part replaces rhenium or optimize craft the low cost to developing our country alloy of the 2nd acting single crystal is very necessary.

The article passes research Re, ta, w, al, the elemental content such as RE can reach the influence of feature of its fracture surface to endurance of high temperature of single crystal alloy, the possibility that rhenium content reduces in exploring single crystal alloy and alloy change new approach. If the watch shows 17 kinds of alloy 1 times,frit of induction of vacuum of element of tall purity of 1 experiment method matchs, vacuum induction is directional and caky below same technology condition preparation single crystal tries board (150mm of × of 15mm × 35mm) , use the heat treatment technology that suits with alloy composition, namely 1340 ℃ of 1310 ～ × 4h, a.

C.

+ 4h of 1100 ℃ × , a.

C.

+ 32h of 870 ℃ × , a.

C.

Be machined next and check, watch 2 show an endurance of its high temperature can. Benefit observes with optics and SEM abiding rupture of sample grand, micromechanism. Express alloy of 1 experiment model alloy of Variation Range Of Main Alloy Elementsof Experimental Model Alloys of 　 of *Table 1 of span of main element content advocate elemental content limits / Wt%WTaNbCrReAl1 ～ 178.

0 ～ 103.

100 ～ of 5 ～ 1.

63.

37 ～ 4.

60.

2 ～ 3.

05.

37 ～ 6.

*Mo of 25 　 　 , co, ti maintain constant, yu Wei Ni; Alloy 2 reach 10, 11 add right amount rare-earth element. Express composition of 2 alloying element the condition of abiding experiment of alloy of Effects Of Content Of Alloying Elementson High Temperature Rupture Properties of 　 of influence Table 2 of abiding to alloy high temperature function and function index ℃ of 980 ℃ 250MPa1070 130 ～ of ℃ of 140 ～ 155MPa1100 140MPa τ / H δ / % φ / % τ / H δ / % φ / % τ .

345.

854.

9---33.

527.

259.

32248.

235.

050.

6---119.

817.

050.

23162.

539.

142.

6---77.

415.

933.

24196.

537.

140.

0122.

2^21.

939.

493.

021.

738.

15211.

843.

037.

592^17.

232.

986.

516.

236.

96184.

131.

437.

3123.

530.

546.

490.

020.

845.

7724328.

530.

3185^23.

638.

0108.

319.

141.

7823324.

732.

5185^22.

839.

5120.

514.

535.

69239.

428.

839.

2152.

519.

241.

4-10387.

546.

445.

4330.

5#22.

436.

4189.

5*10.

436.

11128353.

247.

9239.

5#22.

444.

3227*1639.

4122775445.

5---204*20.

839.

313259.

538.

836.

1---225*12361432046.

536.

4186.

5^17.

929.

6176.

821.

038.

115 ＞ 1915.

36 stop try 21715.

644.

4120.

513.

532.

316 ＞ 2525.

4 stop try 29029.

439.

1115.

513.

444.

37451632748 　 of ＋ of 317263385199 ＋ 4148143174517$2894753104 　 $ : Highest value, the others is average;* : 130MPa, stress of this sample of kind the others is 140MPa;# : 40MPa, ^ : 155MPa, + ^ : 176MPa, stress of this sample of kind the others is 150MPa. 2 tests result 2.

Endurance of 1 high temperature can check a result to express 2 it is to express endurance of high temperature of 1 each alloy to be able to check a result, can discover the following phenomenon from which. (1) alloy 1 less than content of other alloy rhenium, high temperature endurance can be very low. The addition of content of the rhenium in following alloy (0.

3wt% ～ 3.

0wt% ) the abiding function of each temperature all rises gradually. Alloy 16, 14 photographs to alloy 9 reach alloy 1, 3, 4, 5, 7 show Re content increases likewise can make abiding function rises apparently. When adding the element such as rare earth, maintain be more than 2.

0wt%Re (be like alloy 7) it is the requirement that acquires better abiding property, and when should adding right amount rare-earth element (alloy 2) , can make this floor level is reduced apparently. If contain rhenium 0.

8wt% alloy 2 with contain rhenium 2.

0wt% alloy 8 endurance can comparative. Reduce actual alloy to be opposite the demand of rhenium content. (2) can improve the abiding performance of 980 ℃ through raising W and Nb content appropriately, but go against 1100 ℃ abiding function rise, increase Re appropriately, ta, cr, al more those who be helpful for 1100 ℃ abiding function rise. Two kinds in alloying element in be being allocated each other, can rise each other in certain limits, compensate or offset. (A) this effect is alloy 8 with alloy 15 endurance can comparative make clear reduce W and content of Re of Al content meeting countervail increase the result that improves pair of abiding performance. (B) alloy 8 photographs to alloy 5 because of Re, al increases and make 1100 ℃ endurance can increase apparently. Alloy 11, 13 photographs to alloy 9 because of Cr, al aluminous content rises and make especially abiding function especially 1100 ℃ endurance can rise apparently. Alloy 14 photographs to 15 because of Ta, al rises not only the inadequacy that makes up for rhenium content to fall a bit and improve high temperature endurance apparently can. Alloy 10 photographs to alloy 2 reach alloy 11, 13 photographs to alloy 8, 9 because of Ta, al, cr rises appropriately and abiding function is improved apparently. (C) alloy 8 photographs to alloy 7 because of W, al content is reduced apparently and Ta, nb, cr increases apparently and make 1100 ℃ endurance can be improved apparently. (D) alloy 13 photographs of 10 ～ to alloy 14 ～ 16 because of Al, cr, re especially the content of Al rises improving 1100 ℃ high temperature abiding function aspect is strong at pure increase rhenium alloy. (3) matchs tungsten, Tantalum, aluminous, chromic, niobium, content to be able to complement effectively appropriately the alloy of rhenium changes intention. Alloy 6, 7 because aluminium and tungsten content are higher tantalum content is inferior and 1100 ℃ endurance can be inferior, and alloy 7 although alloy changes an element,the quantity is not most but the organization comparatives to be not stabilized. Alloy 8 ～ 13 reach alloy 2 match as a result of better alloying element content, can be in rhenium content is inferior (2.

Alloy is achieved when 0wt%) 14 ～ 16(2.

The abiding function index of 5wt%Re) can exceed greatly even. Preliminary result shows rare-earth element adds the effect remarkable. 2.

Appearance of form of 2 fracture surface observes a result 2.

2.

SEM of 1 abiding fracture surface is organized (Re>2.

0wt%) 　 pursues 1 show an alloy pattern abiding rupture appearance of form of SEM of sample fracture surface. By the graph 1 visible: (Appearance of form of 1)980 ℃ fracture surface by dimension more consistent (50 ～ 80 μ M) , attrib border and erect regulation is out of shape unit small diamonds (001) those who form is scraggly rupture face, discover in border of ministry schism diamonds the edge has the micro-crack of a few bureau part cloth. (2) is out of shape along with experiment temperature unit border bends to become round gradually. At the same time attrib border micro-crack increases as a result to be in along attrib border and patulous limits and width of the crack 1100 ℃ surround whole unit on abiding fracture surface; (3) ruptures heavier abiding life grows face protruding sunken rate more, crackle expands along direction of perpendicular stress axis commonly. Graph feature of appearance of form of SEM of 1 abiding fracture surface 500 × Fig.

500 × of 　 of 1 　 SEM Fractographs Of Rupture Specimens () of A) Alloy14(980 ℃ : 250MPa, 319h; (B)alloy14(1100 ℃ ) : 140MPa, 176h2.

2.

Near 2 abiding fracture surface times lower (did not corrode) the organization pursues 2 show an abiding fracture surface feature of appearance of around macrostructure form. By the graph 2 visible: (1) abiding fracture surface is times lower to contain a certain quantity of protruding sunken step and perpendicular make the same score fracture surface at stress direction, near fracture surface cast blemish basically without large size (shrink loose, be mingled with) , and function jumps over neck of good fracture surface to shrink bigger; (2) the oblique plane slide surface that macroscopical step includes fracture surface to become consistent included angle with sample length or stress direction, reach sample surface from fracture surface sunken reach edge blemish to sample matrix or not dissolve in all the small size concave side that brilliant photograph tears off or crackle; (3) near fracture surface times lower those who be put in different feature is perpendicular the small crackle at stress direction; (4) rise along with temperature, crackle passivation, amount decreases, amount of microcosmic small inclined plane reduces amount of Ju Xiaoao face to increase apparently; (5) when rhenium content is inferior, even if fracture surface is sectional can observe the short flaw with greater width, and crackle distributings centrally around fracture surface, the content that follow rhenium increases, what can raise photograph correspondence with alloy endurance is crackle become petty and in fore-and-aft bigger range (＞ 1cm) existence; (6) trial test makes clear, add right amount rare earth, alloy endurance can be improved apparently. Corresponding hereat fracture surface neck shrinks the quantity increases apparently, fracture surface less than does not have micro-crack and the crackle that arise by the surface almost; (7) oxidation of high temperature surface is serious brittleness is bigger, form a large number of crackle from the surface, abiding function is reduced. 2.

2.

SEM organization observation observes SEM organizes near alloy fracture surface near 3 fracture surface (if the graph shows 2 times) discovery: (1) form of balsa of photograph of ′ of γ of fracture surface place is changed irregular, and be apart from fracture surface to be apart from a bit Yuan Zefa form is changed distributing more regular, namely perpendicular at or adjacent and perpendicular at stress direction; (2) when it is better that rhenium quantity and abiding function are contained in alloy, its are in abiding form of balsa of photograph of ′ of the γ when rupturing is changed present wave model and did not achieve linear model; (3) Chu Rong and not frit in all brilliant photograph or γ ′ photograph, microcosmic shrinkage cavity, oxidation of high temperature surface change infirmly the phenomenon formation that promotes microcosmic crackle and patulous, alloy endurance can be reduced; (4) the form of balsa of γ ′ photograph that added rare-earth element to promote target alloy is changed. 3 results analyse organization of alloy of nickel radical single crystal to include hard the compound between fragile metal the two-phase structure of the γ photograph of γ ′ photograph and solid dissolve aggrandizement. The abiding function of alloy is microcosmic on depend on abiding stress brings to bear on below the condition, the generation faculty that the slippage department such as a fault includes in tenacity γ photograph, wrong motion obstruction and two-phase stress gather capability, the difficulty of photograph of ′ of wrong course γ and micro-crack generation, patulous wait for the kinetic parameter related to temperature stress. This test test temperature is more than 0.

6Tm(Tm is) of alloy melting point, consequently γ ′ acquaintanceship changes a decision to wear alloy endurance can. Its are kinetic accord with Ostwald of γ ′ photograph ripe change academic relation [4] : Among them: T is time; γ  E is γ ′ and γ photograph interface than freedom can; D is in for the solute atom of γ ′ the diffusion coefficient in γ photograph; The solute atom that C  E is γ ′ is in the balance of γ photograph rub Er chroma; V  M is γ ′ rub Er bulk; R is gas constant; T is temperature; H is the particle size of γ ′ photograph. Raise alloy endurance to be able to need it is thus clear that: Proper integral of tall system of γ ′ phase counts V  M(proper form and dimension) , the fault of layer of γ ′ photograph with strong γ and γ ′ aggrandizement of dissolve of solid of multivariate and harmonious sex, tall photograph can, include in γ ′ photograph in γ photograph low diffuse elemental amount, stable γ ′ and γ ′ phase boundary. Because rhenium is γ photograph element of aggrandizement of the soliddest dissolve reachs his to be in because abiding creep process is extremely low diffuse speed greatly slow down creep each are kinetic process and the essential element that becomes alloy of strong abiding performance. Although the action of W is inferior to rhenium but have compensation effect to rhenium. Tantalum, aluminous, niobium and photograph of chromic ′ waiting for γ form an element, especially niobium and Tantalum are strong defer γ ′ ripe change low diffuse speed element, in γ ′ solubility reciprocity requirement falls to be helpful for this photograph amount increasing reach function the content of reasonable aggrandizement direction is adjusted make its endurance can rise, and make this photograph overmuch and too fragile wait for content to adjust abiding to alloy function harmful. These two kinds of elements spend the strong interact that reachs pair of two-phase interface position to ask in alloy solid dissolve between its content harmonious, but the effective compensation action in can using these function at the same time achieves the abiding property with reduce content of some kind of element to come true certain to ask. The article proved to adopt posture of aggrandizement γ ′ of each element content harmonious increase interface of aggrandizement photograph, harmonious two-phase condition and pass at the same time raise alloy to fight oxidisability to be able to rise etc will compensate rhenium content. And rare earth purifies alloy as a result of its, reduce two-phase interface to be able to be mixed raise fault of layer of γ ′ photograph can, raise alloy to fight oxidisability to reach adjust and defer γ ′ photograph the balsa form in abiding creep is changed kinetic wait for a function and be helpful for abiding function improving. Integrated afore-mentioned action can ask to rhenium content can be reduced appropriately below the condition in certain endurance. Graph near 2 abiding fracture surface times lower did not corrode state and SEM γ ′ / Fig of feature of appearance of γ organization body.

2 　 Macrophoto (not Etched)(a) , (′ of γ of B)and SEM / γ Microstructure(c) , (D)in Zone By Rupture Fracture Surface In Longitudinal Section Of Specimens (a)alloy14: 980 ℃ , 250MPa, 387h, 25 × ; (B)alloy16: 1070 ℃ , 155MPa, 25 × of 217h 　 ; (C)alloy2: 1100 ℃ , 140MPa, 93h, 1500 × ; (D)alloy14: 1100 ℃ , 140MPa, 1500 × of 176h 　 4 conclusion 　 (result of 1) initial test makes clear, raise Re appropriately, w, nb, ta, al content is helpful for improving endurance of alloy high temperature can, but strong interact exists between each element. Right amount add rare land effect of function of abiding to improving alloy creep is distinct. (Content of alloying element of 2) experiment proof matchs can optimize abiding function integratedly, implementation replaces rhenium partly. (3) simple analysis makes clear, alloying element content is abiding to rising function action end changes abiding squirm to become kinetic to losing at its especially the integrated intention that γ ′ acquaintanceship changes. CNC Milling