Embodiment
Below, the present invention is at length described.
(1) electric conductivity
If improve electric conductivity, when then material being used as various terminals, junctor, follow the thermal value of energising to reduce.In order to reach the lower calorific value with high beryllium copper equal extent, must be the above electric conductivity of 17%IACS.Preferred electric conductivity is more than 20% IACS.
(2) 0.2% yield strengths
0.2% yield strength is during less than 750MPa, with material during as junctor since the contact place to connect pressure drop low, so the contact resistance increase even electric conductivity is adjusted to more than 17% IACS, can not obtain the low contact resistance with high beryllium copper equal extent.Therefore, 0.2% yield strength is decided to be more than the 750MPa.More preferably 0.2% yield strength is more than the 800MPa.
(3) bendability
When material was used as various terminals, junctor, the balance of 0.2% yield strength and bendability was crucial.The inventor is 1.5-2.3 quality % and the titanium copper that the above electric conductivity of 17% IACS is arranged to Ti concentration, analyze the relation of desired 0.2% yield strength of electronic component and bendability in recent years quantitatively, found that, satisfy certain yardstick that junctor is used with material requirements.Promptly, 0.2% yield strength (YS) and and the vertical direction of rolling direction do not produce be full of cracks when material being carried out W bending (JIS H3130) and between the ratio (MBR/t) of flexible minimum bending radius and thickness of slab, can satisfy the titanium copper of MBR/t ≦ 0.04 * YS-30 relation, make intensity and bending machining sexual balance, can meet requirement in recent years.
(4) Ti content
When titanium copper is carried out ageing treatment, cause poly-partially the decomposition, in mother metal, generate the modulated structure of titanium concentration, can obtain very high intensity thus.Titanium content seldom arrives 0.2% above yield strength of 750MPa during less than 1.5 quality %.On the other hand, when titanium content surpasses 2.3 quality %, the occasion of under the condition of the above electric conductivity of acquisition 17% IACS described later, making, diameter is separated out mutually greater than the thick Cu-Ti intermetallic compound of 2 μ m, so the bendability of material worsens.Therefore, the titanium content of titanium copper of the present invention is 1.5-2.3 quality %, preferably 1.6-2.0 quality %.Moreover the titanium copper of this so far Ti concentration range does not have practicability.Though report is arranged in the Patent Document, not the report that abundant balance is improved intensity, bendability and electric conductivity.For example, the embodiment 1 that the spy opens 2002-356726 has reported that Ti is the alloy of 1.7 quality %, though electric conductivity 20.3% IACS of this alloy and alloy phase of the present invention are together, its 0.2% yield strength is low, is 710MPa.In addition, the embodiment 2 that the spy opens 2002-356726 has reported that Ti is the alloy of 1.5 quality % and 2.3 quality %, but 0.2% yield strength of these alloys is respectively 720MPa and 1180MPa, and electric conductivity is respectively 26.4% IACS and 10.2%IACS, can not have intensity and electric conductivity concurrently.
(5) diameter of Cu-Ti intermetallic compound phase
By Ti is separated out mutually as the Cu-Ti intermetallic compound, can reduce solid solution Ti amount, improve electric conductivity.But, when of the vertical cross-section of rolling direction contains Cu-Ti intermetallic compound minimum circular diameter (maximum diameter of Cu-Ti intermetallic compound phase) mutually and surpasses 2.0 μ m, become the starting point that material bending adds the be full of cracks in man-hour, thereby bendability reduces.Therefore, the diameter of Cu-Ti intermetallic compound phase is decided to be below the 2 μ m.
(6) area occupation ratio of Cu-Ti intermetallic compound phase
In order to improve the electric conductivity of titanium copper, it is crucial fully separating out Ti, doing one's utmost to reduce solid solution Ti amount.That is, if increase the amount of Cu-Ti intermetallic compound phase, then electric conductivity rises.In addition, separate out mutually, also realized the high strength of material by making fine Cu-Ti intermetallic compound.The inventor finds, in the titanium copper that contains Ti 1.5-2.3 quality %, be that the Cu-Ti intermetallic compound area occupation ratio mutually of 0.02-2.0 μ m is that S (%), Ti content are during for [Ti] (quality %) with the diameter of the vertical cross-section of rolling direction, if satisfy the relation of S ≧ 8.1 * [Ti]-11.5, then can obtain the above electric conductivity of 17% IACS.On the other hand, even the diameter of the Cu-Ti intermetallic compound phase of separating out is below the 2.0 μ m, if but S surpasses 7.5%, and then the bendability of material reduces, and difficulty is guaranteed 0.2% yield strength that the present invention stipulates and the balance of bendability.Therefore, the area occupation ratio S that makes Cu-Ti intermetallic compound phase is 8.1 * [Ti]-11.5 ≦ S ≦ 7.5. is in addition, when also finding Ti=1.5-2.0 quality %, if can satisfy the relation of 8.1 * [Ti]-9.5 ≦ S ≦ 7.5, then not only satisfy 0.2% yield strength of the present invention's regulation and the relation of bendability, and can obtain the above electric conductivity of 20% IACS.
(7) average crystallite particle diameter
With the average crystallite particle diameter in the vertical cross section of rolling direction (adopting the JIS H0501 process of chopping to measure) when surpassing 10 μ m, can not realize the high strength of the material due to the crystal grain miniaturization, seldom arrive 0.2% yield strength more than the 750MPa.In addition, if the average crystallite particle diameter is adjusted to less than 2 μ m, then possible residual not re-crystallization part, if residual not re-crystallization part, then bendability worsens.Therefore, be decided to be 2-10 μ m with titanium copper of the present invention with the average crystallite particle diameter vertical cross section of rolling direction.
(8) manufacture method
The inventor finds, in the hot calender of the fusion casting of carrying out raw material successively, ingot bar, cold pressing prolong, solution treatment, cold pressing prolong, in the titanium copper manufacturing process of ageing treatment, colding pressing before the solution treatment prolonged by making respectively, colding pressing after the solution treatment, solution treatment prolonged, ageing treatment is suitable condition, can be met the titanium copper of characteristic of the present invention.Below, creating conditions of each operation described.
Degree of finish is prolonged in colding pressing before the solution processing
When material carried out recrystallization, the strain that utilizes calendering to import became the nucleus of recrystallization grain.It is high more that colding pressing before the solution treatment prolonged degree of finish, can import a large amount of strains more, so the generation of recrystallization grain is remarkable, the growth of crystal grain is inhibited, and can obtain fine crystallization particle diameter.By making colding pressing before the solution treatment prolong degree of finish is more than 89%, can obtain the following average crystallite particle diameter of 10 μ m.
Solution treatment
The solution treatment of titanium copper is generally carried out under the solubleness of Ti and the condition more than the temperature that the concentration of the Ti that is contained equates in Cu.Yet when this temperature range was carried out solution treatment, the crystallization particle diameter surpassed 10 μ m.The inventor has obtained by experiment and has stably obtained the solid solution temperature scope that 2-10 μ m crystallization particle diameter is used.That is, solid solution temperature T (℃) for T〉[6580/{7.35-In[Ti]] under the condition of-273 (x represents Ti content here), the crystallization particle diameter surpasses 10 μ m, seldom arrive 0.2% yield strength more than the 750MPa.In addition, be T<[6580/{7.35-In[Ti] at solution treatment temp T }] under-333 the condition, the crystallization particle diameter is less than 2 μ m, the bendability deterioration of material.By making solid solution temperature T for [6580/{7.35-In[Ti] }]-333 ≦ T ≦ [6580/{7.35-In[Ti] }]-273, the crystallization particle diameter of 2-10 μ m can be obtained.In addition, from the average cooling rate of the material of the Heating temperature to 25 of solution treatment ℃ during less than 300 ℃/s, diameter is separated out at grain boundary in the material cooled process greater than the Cu-Ti intermetallic compound of 2.0 μ m, so when material applied stress in bending, be easy to generate be full of cracks at grain circle.Therefore, the average cooling rate in the solution treatment be set at 300 ℃/more than the s.In addition, the method for cooling of this moment does not have particular determination, but generally carries out water-cooled more.
Colding pressing after the solution treatment prolonged degree of finish
Colding pressing after the solution treatment prolonged degree of finish less than 10% o'clock, can not expect the high strength that work hardening forms, not only seldom arrive 0.2% above yield strength of 750MPa, and because by should tailing off that calendering imports, so in the ageing treatment of subsequent processing, the speed of separating out of Cu-Ti intermetallic compound phase is slow, and is rare to the electric conductivity more than 17% IACS.In addition, degree of finish surpasses at 70% o'clock, and therefore the obvious deterioration of bendability because ductility reduces, seldom arrives 0.2% yield strength of the present invention's regulation and the relation of bendability.Therefore, colding pressing after the solution treatment prolonged degree of finish and is set at 10-70%.In order to obtain the relation of better 0.2% yield strength and bendability, it is 40-65% that colding pressing after the preferred solution treatment prolonged degree of finish.
Ageing treatment
In the ageing treatment, for the Cu-Ti intermetallic compound that the present invention is stipulated is separated out mutually, adjusting aging condition for example as described below.
(1) Heating temperature
Heating temperature is during less than 350 ℃, and separating out of Cu-Ti intermetallic compound phase is insufficient, can not obtain 0.2% above yield strength of 750MPa, the above electric conductivity of 17% IACS.In addition, when Heating temperature surpasses 450 ℃, because the Cu-Ti intermetallic compound carry out thickization mutually, so intensity and bendability reduce.Therefore, Heating temperature is decided to be 350-450 ℃.The Heating temperature here is the temperature of stove that material is heated.
(2) hold-time under the Heating temperature
Hold-time under the Heating temperature, separating out of Cu-Ti intermetallic compound phase was insufficient during less than 5 hours, and be rare to the electric conductivity more than 17% IACS.Hold-time under the Heating temperature is when surpassing 20 hours, because the Cu-Ti intermetallic compound carry out thickization mutually, so intensity and bendability reduce.Therefore, the hold-time under the Heating temperature is decided to be 5-20 hour.The hold-time here is that the temperature of material reaches after the temperature of stove, until the time that begins to cool down.
(3) average cooling rate
In the ageing treatment, when faster,, do not cause separating out of sufficient Cu-Ti intermetallic compound phase although obtain the above electric conductivity of 17% IACS than 50 ℃/hour from the even speed of cooling of Heating temperature to 200 ℃.In addition, average cooling rate is during less than 10 ℃/hour, the separating out obviously of Cu-Ti intermetallic compound phase, and the area occupation ratio of the Cu-Ti intermetallic compound phase of diameter 0.02-2.0 μ m surpasses 7.5%, so the bendability deterioration.Therefore, the average cooling rate of the Heating temperature to 200 from ageing treatment ℃ is decided to be 10-50 ℃/hour.
[embodiment 1]
As raw material, use high frequency vacuum melting stove with electric copper, behind ingot (wide 60mm * thick 30mm) melt-casting with various compositions shown in the table 1, become 8mm 900 ℃ of following hot calender.Then, carry out under the conditions shown in Table 1 that colding pressing before the solution treatment prolonged, colding pressing after the solution treatment, solution treatment prolonged and timeliness is handled, and the size and the area occupation ratio of average crystallite particle diameter, Cu-Ti intermetallic compound phase are changed.In addition, in the solution processing, after the temperature that reaches table 1 for the temperature of test materials, kept 1 minute, cool off then.In this cooling, change, adopt air cooling, spray Ar gas, water spray, the method for flooding in tank cool off, and in addition, changes the emitted dose of Ar gas and water in order to make speed of cooling.Thermopair is welded on on the test materials, measures the average cooling rate that reaches 25 ℃ (room temperatures) for the temperature of test materials.In the ageing treatment, by the temperature change speed of cooling of control stove, measure temperature for test materials from Heating temperature to the average cooling rate that is 200 ℃.
To each alloy that makes like this, estimate 0.2% yield strength, electric conductivity, bendability (MBR/t), with the average crystallite particle diameter and Cu-Ti intermetallic compound size, the area occupation ratio mutually in the vertical cross section of rolling direction.
To 0.2% yield strength, use tensile testing machine to measure according to JIS Z2241.To electric conductivity,, adopt 4 terminal methods to measure according to JIS H0505.Evaluation to bendability, adopt the rectangle test portion of wide 10mm, long 50mm, the vertical and vertical direction of rolling direction (Bad way) at test portion is carried out W pliability test (JISH3130) by various bending radius, the metewand that the technological standard JBMA T307:1999 of copper association is stretched in bend convex surface outward appearance and Japan compares, and obtains the ratio (MBR/t) of the minimum bending radius (mm) that do not produce be full of cracks and thickness of slab (mm).
When measuring average crystallite particle diameter (μ m), to carrying out etching (water (100ml)-FeCl with the vertical cross section of rolling direction
3(5g)-HCl (10ml)), crystal grain is exposed, observe by scanning electron microscope, adopt the process of chopping (JIS H0501) to calculate the crystallization particle diameter.
To the observation of the Cu-Ti intermetallic compound phase separated out in the alloy, (Japanese エ Off イ-ア イ Co., Ltd. system XL30SFEG) carries out to use FE-SEM.After grinding the vertical cross section of rolling direction with material with the water-fast pouncing paper of #150, use muddiness to have the polishing of the colloid silica of particle diameter 40nm to carry out mirror ultrafinish with abrasive, the test portion that obtains is carried out the carbon evaporation,, under 10,000 times multiplying power, observe the 100 μ m of 5 places because of each alloy changes the visual field
2The reflection electronic picture in the visual field.Then, use image analysis apparatus to obtain minimum circular diameter and the area occupation ratio that contains Cu-Ti intermetallic compound phase in the observed visual field.When estimating Cu-Ti intermetallic compound phase big or small, for the alloy that exists diameter to surpass 2.0 μ m Cu-Ti intermetallic compound phases be evaluated as *, be evaluated as zero for the alloy that does not exist diameter to surpass 2.0 μ mCu-Ti intermetallic compound phases.In addition, when estimating area occupation ratio,, the total area of Cu-Ti intermetallic compound phase is removed value that the total area of field of view the obtains area occupation ratio as Cu-Ti intermetallic compound phase as the diameter 0.02-2.0 μ m of the Cu-Ti intermetallic compound phase of determination object.
The evaluation result of each alloy is shown in table 2.Example 1-10 all satisfies Ti content, the crystallization particle diameter of the present invention regulation, the size and the area occupation ratio of Cu-Ti intermetallic compound phase, so demonstrate the above electric conductivity of 17% IACS, 0.2% yield strength that 750MPa is above, in addition, 0.2% yield strength (YS) also satisfies scope of the present invention with the relation of MBR/t.Particularly, Ti content is in the scope of 1.5-2.0 quality %, and the area occupation ratio S of Cu-Ti intermetallic compound phase satisfies the example 2,4,7 of 8.1 * [Ti]-11.5 ≦ S ≦ 7.5 and 10 electric conductivity surpasses 20%IACS.In addition, Ti content is in the scope of 1.6-2.0 quality %, and the example 2 and 5 of the rolling processing degree after the solution treatment in the 40-65% scope, compare with other embodiment, demonstrate excellent in vending workability (MBR/t) in the equal occasion of 0.2% yield strength, and demonstrate 0.2% high yield strength in the equal occasion of bendability.
On the other hand, comparative example 11 is because Ti concentration is too low, so can not obtain 0.2% above yield strength of 750MPa.
Comparative example 12 is too high owing to Ti concentration, thus separate out the thick Cu-Ti intermetallic compound phase of the above size of 2.0 μ m, and because the area occupation ratio of Cu-Ti intermetallic compound phase surpasses scope of the present invention, so can not obtain bendability of the present invention.
Comparative example 13 is because the degree of finish before the solution treatment is low, so the average crystallite particle diameter after the solution treatment surpasses 10 μ m, 0.2% yield strength can not reach 750MPa.
Comparative example 14 solid solution temperatures are lower than scope of the present invention, residual not re-crystallization part, in addition since the size of Cu-Ti intermetallic compound phase, area occupation ratio all above scope of the present invention, so can not obtain the bendability that the present invention stipulates.
Comparative example 15 can not obtain 0.2% above yield strength of 750MPa because solid solution temperature than scope height of the present invention, so the average crystallite particle diameter surpasses 10 μ m, carries out the occasion of ageing treatment under the condition that obtains the electric conductivity more than 17% IACS.
Separate out mutually by the thick Cu-Ti intermetallic compound above size of 2.0 μ m because the average cooling rate after the solid solution is slow for comparative example 16, so can not obtain the bendability of the present invention's regulation.
Comparative example 17 is because the rolling processing degree after the solution treatment is too low, so can not obtain 0.2% above yield strength of 750MPa, and the area occupation ratio of Cu-Ti intermetallic compound phase is lower than scope of the present invention because the Ti speed of separating out in the timeliness is slow, so can not obtain the above electric conductivity of 17% IACS.
Comparative example 18 is owing to the rolling processing Du Taigao after the solution treatment, so can not obtain the bendability of the present invention's regulation.
Comparative example 19 is because the Heating temperature in the ageing treatment is too low, so because thereby underaging can not obtain 0.2% above yield strength of 750MPa, and because the area occupation ratio of Cu-Ti intermetallic compound phase is lower than scope of the present invention, so can not obtain the above electric conductivity of 17% IACS.
Comparative example 20 is because the Heating temperature in the ageing treatment is too high, so thereby because overaging causes thickization of Cu-Ti intermetallic compound phase, can not satisfy 0.2% yield strength of the present invention's regulation and the relation of bendability.
Comparative example 21 is because the area occupation ratio short, Cu-Ti intermetallic compound phase of the heating hold-time in the ageing treatment is lower than scope of the present invention, so can not obtain the above electric conductivity of 17% IACS.
Comparative example 22 is owing to the heating hold-time in the ageing treatment is oversize, so thereby because overaging causes thickization of Cu-Ti intermetallic compound phase, can not satisfy 0.2% yield strength of the present invention's regulation and the relation of bendability.
Comparative example 23 is because the area occupation ratio fast, Cu-Ti intermetallic compound phase of the average cooling rate in the ageing treatment is lower than scope of the present invention, so can not obtain the above electric conductivity of 17% IACS.
Comparative example 24 is because the average cooling rate in the ageing treatment is slow, the area occupation ratio of Cu-Ti intermetallic compound phase surpasses scope of the present invention, so can not obtain the bendability of the present invention's regulation.