IDEA Executive summary

Transcription

1 IDEA AST3-CT Executive Summary Rev. 1.0 Page 1 of 6 IDEA Executive summary The project aims at substituting aircraft components like electronic casings, cabin equipment, and seat frame parts by cast magnesium parts. Integration of Mg alloys into the aerospace will lead to breakthroughs, which will reduce the airplane s weight, improve the noise damping and reduce the fuel consumption and air pollution. Nowadays less than 20 Mg-casting alloys are available, however more than 97% of the castings are made of AZ91, AM50 (or AM60) and WE54, from which only the WE54 is used in the aviation industry. Thus, there is a need to increase the number of Mg-alloys available for aerospace applications with their specific requirements to strength, damping properties, corrosion resistance etc. Since there is an obvious lack of knowledge about the characteristics and advantages of this magnesium and it s alloys and a lack of approved standards for magnesium components another important aim of the project is to inform aviation designers broadly on the usability of Mg-alloys and to contribute to standardisation. Accordingly, the technical objectives of the project are: 1. To develop new lightweight Mg-alloys, which fulfil the requirements for, castability, corrosion resistance and mechanical properties of the cast components. 2. To optimise the most appropriate casting technologies (investment casting, sand casting, gravity die-casting, but also high pressure die-casting) processes for Mg alloys. 3. To develop and use specific simulation tools for determination of local mechanical part properties and virtual standard tests of cast components. 4. To prepare a design manual for cast magnesium components in aeronautic applications. The manual is aimed to be a guide for aviation designers to select convenient Mg-alloys and production methods for convenient aircraft components. 5. To produce demonstrator castings for typical thick-walled and thin-walled aerospace applications. The consortium consists of 13 partners of which 6 are companies (including 5 SME s), 5 are research institutes or research companies including one of the SME s - and 3 are Universities. The members of the consortium are the simulation software developer RWP GmbH (D), the Israel Institute of Technology Technion (IL), the Magnesium Research Centre MRI (IL), the end user Israel Aircraft Industries IAI (IL), the light-metal foundries Specialvalimo J. Pap SV (FI), Femalk (HU), and Stone (UK), the Technical Research Centre of Finland VTT (FI), the research company INFERTA GmbH (D), TECOS - the Slovenian Tool and Die Development Centre (SI), the LCSM of the University of Nancy (F), MGEP - the University of Mondragon (ES), and the Fraunhofer Institute IST (D). The project is co-ordinated by RWP. Contact Information: Dr. Achim Wendt RWP GmbH Am Münsterwald 11 D Roetgen a.wendt@rwp-simtec.de Tel

2 IDEA AST3-CT Executive Summary Rev. 1.0 Page 2 of 6 The project follows three main tracks: Development of new Magnesium alloys with improved mechanical and corrosion properties. Surface treatment and corrosion protection. Development and optimisation of casting processes including simulation tools and design rules. In the first project year efforts were concentrated on the development of new magnesium alloys, characterising corrosion behaviour of commercial Mg-alloys and development of casting technologies including simulation methods. The alloys and castings developed in the project will be mostly used in the Business Jet Gulfstream 200 manufactured by Israel Aircraft Industries, Figure 1. Several reference parts, which shall be used to demonstrate the project achievements with respect to alloy properties, casting technologies and mechanical properties of the casting have been selected for production. The selected parts, a mechanical housing and a pedal, are shown in Figures 2 and 3. The mechanical properties to be fulfilled are given in Table 1. Figure 1. Gulfstream G200 Figure 2. Reference part Housing. Figure 3. Reference part Pedal. Alloy development New magnesium alloys with increased strength and good corrosion resistance have been developed. The alloys comprise different groups, which are suitable for sand casting, investment casting, permanent mould casting, high-pressure die-casting. Both die-casting and gravity casting alloys were developed both for thin-walled and thick-walled castings as well. The alloy development is based on the partners experience, theoretical consideration using thermodynamic assessment and practical experimentation using state of the art facilities available at partners.

3 IDEA AST3-CT Executive Summary Rev. 1.0 Page 3 of 6 Table 1. Technical requirements to Magnesium parts. TYS 220, UTS 290, Elongation -3% Axial fatigue strength for 10 6 cycles - minimum 0.28 UTS at R=-1 and 0.5 UTS at R=0.2 Thermal conductivity 100 W/m*K Strict requirements to general and galvanic corrosion Out of the six new alloys, which have been developed for high-pressure die-casting, one was selected for production of reference parts. Three new alloys have been developed for die-casting, Investment casting and Sand casting. The mechanical properties of the selected alloys are listed in Table 2. Table 2. Mechanical properties of the new Mg-alloys for die-casting, Investment casting and Sand casting (T6 state) and High Pressure Die Casting (not heat treated). MRI 204 MRI 205 MRI207 MRI 207 Alloy 1 HPDC AZ91D HPDC TYS 219 ± ± ± ± UTS 270 ± ± ± ± ± E % 3 ± 1 10 ± ± ± ± 0.5 Figure 4 shows the superior fatigue properties of MRI 204 and MRI 205 compared to the widely used Al357 Aluminium alloy. Fatigue testing results of Sand-cast MRI 204 and MRI 205 in T6 state are shown in Figure 4. The solid lines presents values typical for Al357 in T6 state Stress [] Axial fatigue behavior of MRI 205-T6 200 R = Mean value UTS = Run-Out Lower limit E E E E E E+08 Cycles Stress [] Axial fatigue behavior of MRI 204-T6 200 R = Mean value UTS = Lower limit E E E E+06 Cycles Figure 4: Fatigue test results for Sand-cast MRI 205 and MRI 204. The solid lines present values typical for Al357 in T6 state. The blue squares present the measured values of MRI 204 and MRI205 in T6 state. The alloys selected for production of reference parts are Alloy 1 for HPDC, MRI 205 for gravity die casting as well as MRI 204 and MRI 207 for Investment casting and Sand casting. The mechanical properties of the selected alloys meet the requirements given in Table 1 and are better than these of Al357, which is a typical cast Al-alloy for aerospace applications.

4 IDEA AST3-CT Executive Summary Rev. 1.0 Page 4 of 6 Corrosion Corrosion research focused on investigation of the commercial alloys AM50 and AZ91D and the new developed HPDC-alloy. The performed tests covered EIS in ASTM D water, Immersion tests in ASTM D water and climatic chamber tests. Furthermore the formation of conversion coatings on AM50 and AZ91 were researched using Chromatation, Phosphatation and Carboxylation and various industrial coatings. The conversion coatings were characterised by EIS, immersion tests, climatic chamber tests, pitting evaluation and SEM & EDS analysis. Comparisons of all RHF values obtained at the corrosion potential for the converted surfaces showed the same mechanism of protection on a reduced surface. Conversion coatings Chromate coating seems to be the best. Phosphate-permanganate coatings are almost as good as the chromate coatings. Oxsilan commercial coating is less good than chromate and phosphatepermanganate coatings. Carboxylate coating seems to be very promising but needs to be improved. Its use is very interesting because it is environment- friendly compared to chromate or phosphate-permanganate coatings. Anodization Commercial Algan 2M gives some good results with the commercial alloys. The sealing needs to be improved. Investment casting Partner VTT investigated mould-metal reactions between investment cast magnesium alloy and different refractories. Excellent reaction resistance was seen in the case of fused magnesia and yttria face coated shells. Fused alumina and zircon also showed good resistance. molochite and zirconia provided moderate to poor reaction resistance. Strong metal-refractory reactions were observed in the case of fused silica. As a result a shell mould has been developed which is less reactive with Magnesium alloys than commonly used shells. Partner Stone Foundries investigated optimum mould and metal casting temperatures as general guidelines for small to medium size castings with 2mm to 3mm wall thickness. The results predictably show the lower mould and metal temperatures lead to misrunning of wall thickness between 2mm and 3mm and high temperatures generated excessive shrinkage defects. Results indicate the optimum mould temperature to be 400 o C 430 o C and metal pouring temperature of 730 o C 750 o C to achieve casting wall thickness 2mm 3mm. These temperatures are to be used as guidelines for future development. Casting process development and simulation. In order to study the influence of different casting processes to mechanical properties and corrosion behaviour appropriate specimens for mechanical testing and corrosion testing have been selected. Specimens and test geometry have been produced by sand casting, gravity diecasting, high-pressure die-casting, and investment casting and were tested for mechanical properties and corrosion behaviour. Also reference castings like these shown in Figures 2 & 3 have been selected. Casting of the reference parts is ongoing, respectively in the planning phase. The properties of castings made from the new developed alloys are listed in Table 2 and presented in Figure 4.

5 IDEA AST3-CT Executive Summary Rev. 1.0 Page 5 of 6 Material laws have been derived from measurements, which allow the simulation of local mechanical properties in castings. The laws are implemented in the commercial simulation software WinCast and currently under verification. Calculated Tensile strength and Ultimate strength for HPDC AZ91D are given in Figures 5 & 6 respectively. The calculated values are very close to typical measured values. Figure 5 : Calculated TYS for HPDC AZ91D. Calculated 177, typical 160 Figure 6 : Calculated UTS for HPDC AZ91D. Calculated 257, typical 260. The grain size of die cast material as a function of the casting's wall thickness is presented in Figure 7. Figure 7 : Grain size as a function of the product's wall thickness. The selected test part, the so-called VW-plate, has been cast and characterised. The commercial alloy AZ91 was characterised for sand, investment, gravity die-casting and HPDC and the new MRI207 alloy for gravity die-casting. The VW-plate is a thick walled part and it was selected because it is a difficult part to cast and to verify defect criteria and material laws. This complexity causes that the quality is reduced with higher defect levels, so the mechanical properties are reduced. Anyway, the first results with the new alloys show that the new alloys are able to obtain even geometries which are difficult to cast.

6 IDEA AST3-CT Executive Summary Rev. 1.0 Page 6 of 6 Table 3. Mechanical properties of the commercial and new Mg-alloys for die-casting, Investment casting and Sand casting (T6 state) and High Pressure Die Casting (not heat treated). MRI207 Investment AZ91D HPDC TYS ± UTS ± E % 5.5 ± Dissemination and exploitation. The project has been presented at several conferences, seminars and workshops in Europe, at the TMS 2005 conference in San Francisco, USA (February 2005) and at the MS&T05 conference in Pittsburgh, USA (September 2005). The new alloys and their properties will be presented in 7 th International Conference on Mg alloys to be held in Dresden (November 2006). The main dissemination and exploitation activities within the project frame of activities were the following: Establishment of an Advisory Board (AB). Development of project website. Contribution to conferences and publications. Further exploitation measures A Magnesium process- and simulation database and a design manual for aircraft designers are under development. Apart from information on alloys, their mechanical, physical and corrosion properties the database and the Design Manualk will also contain characteristics of casting process technologies and design principles. The Advisory Board members participate by contributing according to their own expertise. Part of the Magnesium database will be published and made accessible through the IDEA website. The results of the project will be measured in three phases: Short term measure (up to 2 years after project finalization): Implementation of cast Mg components in IAI airplanes. Medium measures (2-5 years after project finalization): This is the outcome followed by the second wave of AB member s exploitation activities. Successful outcome of this stage will be the use of cast Mg applications by other aerospace companies. Long term measure (5-10 years after project finalization): Mg is an attractive and competitive material for the aviation industry.