1、 STD-AECMA PREN 2007-ENGL 1997 = LOL23LL 001307L L55 M Edition approved for publication Comments should be sent within six months after the date of publication to AECMA STANDARD NORME AECMA AECMA NORM C5 Chairman prEN 2007 Edition P 1 May 1997 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUS
2、TRIES (AECMA) Gulledelle 94 - 8-1200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : Descriptors : ENGLISH VERSION Aerospace series Test methods for aluminium and aluminium alloy products Metallographic determination of cladding thickness and copper diffusion in the cladding for roll
3、ed products Srie arospatiale Luft- und Raumfahrt Mthodes dessais applicables aux produits en aluminium et en alliages daluminium Dtermination mtallographique de lpaisseur du placage et de la diffusion du cuivre dans le placage applicable aux produits lamins Prfverfahren fr Erzeugnisse aus Aluminium
4、und Aluminiumlegierungen Metallographische Bestimmung der Dicke der Plattierung und Kupferdiffusion in der Plattierung bei gewalzten Erzeugnissen This “Aerospace Series Prestandard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published
5、 on green paper for the needs of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangea
6、bility is affected, physically or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN (Europ
7、ean Committee for Standardization) for formal vote. 1997-05-30 AECMA Gulledelle 94 Mr Odorico B-1200 BRUXELLES aecma 199 Page 2 EN 2007 : 1997 Contents O Introduction 1 Scope 2 Normative references 3 Metallography 4 Measurement of cladding thickness 5 Measurement of copper diffusion in the cladding
8、6 Test report STD-AECMA PREN 2007-ENGL 1977 1012311 OOL3073 T28 W Page 3 prEN 2007 : 1997 O Introduction This standard is part of the series of EN metallic material standards for aerospace applications. The general organization of this series is described in EN 4258. 1 Scope 1 .I cladding for rolled
9、 aluminium alloy products. This standard specifies the procedures for measuring cladding thickness and copper diffusion in 1.2 user of this standard to adopt appropriate health and safety precautions. This standard does not consider health and safety requirements. It is the responsibility of the 2 N
10、ormative references This European Standard incorporates by dated or undated reference provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions
11、of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 4258 Aerospace series - Metallic materials - General organization of standardization - Links betwee
12、n types of EN standards and their use 1) 3 Metallography 3.1 Sample preparation A sample, at least 20 mm long in the long transverse direction, shall be taken from the full thickness of the sheet, strip or plate as shown in figure 1. This should be mounted and mechanically polished for metallographi
13、c examination of the cross section using a technique which ensures satisfactory retention of the sharp sample edge. This is necessary for the accurate measurement of the cladding thickness and copper diffusion. The use of electro-polishing is not recommended as dissolution of the cladding is possibl
14、e leading to a loss of edge definition and reduced accuracy. Figure 1 1) Published as AECMA Prestandard at the date of publication of this standard 3.2 Etching This is a two stage process where the micro-sample is initially etched by immersion in the etchant to reveal the clad layer (see 4). An addi
15、tional immersion etch is then required to reveal the extent of the copper diffusion (see 5). It is important not to remove any etching products from the sample surface at any stage during the entire etching process. The etchant shall be freshly prepared, used in the temperature range of 15 OC to 30
16、OC and of the following composition : Reagents Quantity ml I hydrochloric acid (p = 1 ,I 9 g/ml) I 1,s I I nitric acid (p = 1,38 g/ml to 1/40 g/ml) I 23 1 I hydrofluoric acid (40 % concentrated) -1- 0,5 to 1,O-l I distilled (or deionised) water I to loo-( After etching the sample should be rinsed in
17、 cold running water followed by hot air drying. Care should be taken not to rub the sample surface. 4 Measurement of cladding thickness The polished micro-sample shall be initially etched for 10 s and examined at a suitable magnification between 100 x and 500 x. Cladding thicknesses shall be measure
18、d in at least five locations, a minimum of 3 mm apart, on each side of the product. The mean cladding thickness c, for each side, is the arithmetic mean of the values measured. The results shall be presented as a percentage of the actual thickness of the product. 5 Measurement of copper diffusion in
19、 the cladding 5.1 The micro-sample used for measuring the clad thickness in 3 shall then be immersed (without re-polishing) for a further 20 s in the etchant to reveal the extent of the copper diffusion. The cross section shall be examined at a suitable magnification between 100 x and 500 x. The dif
20、fusion front is identified by a change of colour in the cladding from dark to light. It generally consists of a succession of peaks (enhanced diffusion along the grain boundaries) and valleys. Conventionally, the mean position of the diffusion front, for the field under examination, shall be taken a
21、s the valley bottom closest to the surface of the product. Its distance from the core-cladding interface, b (see figures 2 and 3), shall be measured on that side of the sample with the minimum cladding thickness, at five locations, at least 3 mm apart from each other. The largest b value measured sh
22、all be retained to represent copper diffusion. The result shall be expressed as a percentage of the mean cladding thickness c, as determined under 3, .e. : x 100 b max. copper diffusion = - c NOTE : In cases where the core/cladding interface is not clearly defined it is permissible to measure the mi
23、nimum d value in lieu of the maximum b value (see figures 2 and 3). In this instance copper diffusion is expressed as follows : -min. copper diffusion = c STD-AECMA PREN 2007-ENGL 1777 LOL2313 0033075 BTO Page 5 prEN 2007 : 1997 cladding - core Figure 2: 20% copper diffusion 4 I I Figure 3: 40% copp
24、er diffusion 5.2 Other methods to evaluate copper diffusion may be used such as optical emission spectroscopy, coloured etching, etc. ; however this shall be specified on the order. The method used shall be agreed between the manufacturer and the purchaser. It shall be calibrated using reference sam
25、ples, the copper diffusion of which has been determined according to 5.1. The reference samples used shall be of the same material, temper and thickness as the rolled product to be inspected. 6 Test report The test report shall contain the following information : - reference to this standard, - the method used if different from the above, - reference of the inspected product, - mean cladding thickness on each side of the product, - maximum copper diffusion observed on the sample (when applicable).
