鋁合金外文翻譯--熱電勢和電功率表征2024航空鋁合金的固溶和時效過程(英文）

1、ELSEVIER Thermoelectric Power Characterization of a 2024 Aluminum Alloy During Solution Treatment and Aging Daren Sun,*+ Xi-then Sun,* Derek 0. Northwood,” and Jerry H. Sokolowski” *Engineering Materials Group, Depa

2、rtment of Mechanical and Materials Engineering, University of Windsor, Windsor, Ontario, N9B 3P4, Canada, and +Engineering Materials Department, Jilin University of Technology, Changchun, Peoples' Republic of Ch

3、ina The solution treatment and aging of a 2024 aluminum alloy was studied using the thermo- electric power (TEP) measurement technique, and the results compared to those obtained by microhardness and optical microsc

4、opy. The TEP value changes with solution treatment temperature and duration and reaches a maximum value for solution treatment at 500°C. The changes in TEP during solution treatment are caused by changes in the

5、solubility of the alloying elements in o-Al. In the artificial aging process, the TEP value decreases with in- creasing aging time, but exhibits different characteristics for different stages of aging. In the initial

6、stage, the TEP value decreases slowly and shows a fluctuating behavior for aging in temperatures below 190°C. This fluctuation is caused by G.I? zone, G.P.B. zone, e”, 8’, S”, and S’ formation which make differe

7、nt contributions to the TEP value. The TEP values cor- responding to maximum microhardness for different aging temperatures are the same for a given solution treatment temperature. After the peak age, the TEP valu

8、es decrease very quickly because the solubility of the alloying elements in CY-Al decreases with aging time. The micro structural changes caused by precipitation during aging which cannot be ob- served by the lig

9、ht optical microscope were successfully monitored by the TEP measure- ment technique. INTRODUCTION system [2] (see Fig. 1) as an example. At temperatures below the solidus, the equi- The aluminum alloy 2024 is w

10、idely used in librium state consists of two solid phases: (Y aircraft structures, rivet hardware, truck solid solution and an intermetallic-com- wheels, screw machine products, and other pound phase, 8 (AlzCu).

11、The solid solubil- miscellaneous structural applications [ 11. It ity of copper in the aluminum solid solu- is a precipitation-hardening alloy which is tion increases as the temperature increases, subjected to

12、a solution treatment, quench- and at temperatures above the lower curve ing, and an artificial aging treatment in or- (solidus), copper is completely soluble in der to obtain the optimum combination of a-Al.

13、However, at temperatures above the mechanical properties. incipient melting temperature (the solidus The solution treatment results in the dis- line), the solubility of copper in aluminum solution of solid phas

14、es, and the tempera- decreases with increasing temperatures be- ture for this treatment must be carefully cause of formation of a liquid phase which chosen. The solubility-temperature relation- contains a highe

15、r copper content than in ships can be illustrated by using the Al-Cu the solid. Therefore, the solution tempera- 83 MATERIALS CHARACTERIZATION 36:83-92 (1996) 0 Elsevier Science Inc., 1996 655 Avenue of the America

16、s, New York, NY 10010 1044-5803/96/$15.00 I’11 S 10445803(96)00002-2 TEP Characterization of a 2024 Al Alloy 85 OP-S SiO2 (<lkm) slurry. The samples were then etched using a solution of 200ml H20:5ml HN03:3ml

17、 HCl:2ml HF. The spec- imens were then examined under the light optical microscope at a magnification of X 100 and X 500. THERMOELECTRIC POWER AND MICROHARDNESS MEASUREMENTS Figure 2 shows the principle of the

18、TEP measurement system. Two copper blocks A and B were maintained at temperatures of T (15OC) and T + AT (25”C), respectively. The specimen was pressed into these Cu blocks to ensure a good thermal and electri- cal

19、 contact. A voltage, AV (kV) is generated across the specimen. The TEP values, AS, are calculated using equation [14] AS = AVIAT A more detailed description of the TEP measurement system can be found in Northw

20、ood et al. [15]. Microhardness was measured with a load of lOOg, a diamond pyramid indentor, and test time of 15 s. A minimum of six readings were taken randomly for each hardness determination to provide a st

21、atis- tical basis for the mean hardness values. EXPERIMENTAL RESULTS AND DISCUSSION EFFECT OF SOLUTION TREATMENT TEMPERATURE AND DURATION The variation in TEP values, AS (kV/K), and the microhardness as a functio

22、n of so- lution treatment temperatures are shown in Fig. 3. Below 5OO”C, the TEP values and the MA d, t \ BbCkB T TCI TC2 TSAT , 4 I 4 FIG. 2. Schematic diagram showing the experimental setup for the TEP me

23、asurements. I _~.~~i +“l(fā)Cker* m,crahardnesa. H” &TEP FIG. 3. Effect of solution temperature on TEP value and microhardness of 2024 aluminum alloy. microhardness increase with increasing so- lution treatment

24、 temperature, reaching a maximum value at about 5Oo”C, before decreasing with further increases in tem- perature. Figure 4 shows the relationship between the TEP and the duration of the solution treatment for

25、 the samples solution-treated at 500°C. It can readily be seen that initially the TEP values increase rapidly with time before reaching an approximately constant TEP value after 3 minutes of treatment. Recent s

26、tudies have clearly shown that the TEP values measured at ambient tem- perature (20°C) are sensitive to the amount of alloying elements in solid solution [9,10, 161. As previously noted, for most alumi- num al

27、loys, the solubility of the alloying el- ements in solid solution changes with the solution treatment temperature and time. The Al-Cu phase diagram, shows that the solubility of copper in a-Al solid solution increa