Prediction of earing of aluminium sheets from {111} pole figures

Crystallographic texture causes anisotropic formability of metal sheets, which results in the formation of uneven cup heights during deep drawing, called earing. Over the past decades, several methods had been developed to predict the earing behaviour of aluminium alloys. These methods are rather complex and can only be applied within strict sheet thickness ranges. Recently, a simple method has been presented and successfully applied on different sheet thicknesses. The method relies solely on {h00} type pole figure data. However, it is desired to be able to predict earing from other reflections as well. In this manuscript, a method which predicts the type and magnitude of earing only from the data of {111} pole figure measurements, is presented. The method was applied on a series of 0.3 mm and 3 mm thick cold rolled and annealed aluminium sheets, exhibiting rolling and recrystallization textures and the combination of these. It is shown that the proposed method gave similar results to those of deep drawing tests. It is concluded that using the presented method, the earing of aluminium sheets can be characterized solely from {111} pole figure measurement data

Non-destructive texture measurement methods for centreless X-ray diffractometers in reverse modified Χ (CHI) mode

Conventional X-ray diffraction-based pole figure measurements have been carried on with dedicated instrument which are accompanied with certain limitations such as sample size, geometry, and no possibility for on-site measurements. These restrictions limit the availability of texture measurements to situations in which cutting a small sample from large parts is difficult or even not allowed at all. The present paper introduces new texture measurement method developed on mobile centreless X-ray diffractometers which are originally applied for residual stress measurements. The essence of this new method, named reverse modified mode is that it uses the data obtained by residual stress measurement to describe anisotropic characteristics, even to the determination of pole figure. Using this method, pole figures can be obtained with all the benefits of centreless diffractometers: no need for sample cutting, flexibility in case of large components with complex shapes, short measuring time and portability. The obtained pole figures are equivalent to the pole figures determined by conventional diffractometers. The presentation describes the measurement method and includes the validation with conventional pole figure measurements and provides instances of applications of the new technique

Earing Prediction of Unidirectionally and Cross-rolled, Annealed AW-5056 Al Sheets from {h00} Pole Figures

Earing of deep drawn cups is an effective measure of plastic anisotropy. It is the result of crystallographic anisotropy, i.e. texture. There are several methods to predict earing, but all of these methods are rather complex. Furthermore, above a certain sheet thickness, deep drawing cannot be performed, and prediction methods fail since they are usually valid within a certain sheet thickness range. A new, simple method has been proposed to predict earing. Besides simplicity, another major benefit of the method is that it can be applied to a wide range of sheet thicknesses. The method has been previously applied for unidirectionally rolled and recrystallized and cross-rolled Al sheets. In the present manuscript, the proposed method is applied on the AW-5056 type, unidirectionally and cross-rolled, then annealed Al sheets having very weak (close to random) structure. It is shown that for such samples, the method predicts negligible earing. It is also revealed that for the 5056 type Al alloy, the differences in texture and earing between unidirectionally and cross-rolled samples become so small after annealing, that the benefit of cross rolling is negligible

Ipari forrasztószerszámok tönkremeneteli mechanizmusa

A tanulmány egy az ólommentes forraszolvadékok által jól nedvesíthető, iparban használt forrasztószerszám tönkremeneteli mechanizmusát mutatja be az ólommentes forraszanyagok károsító hatásának következtében. A forrasztószerszám alapanyagának szövetszerkezeti vizsgálatát optikai mikroszkóppal (OM) és pásztázó elektronmikroszkóppal (SEM) végeztük el. A fúvóka / forraszolvadék határfelületen lejátszódó fizikai-kémiai folyamatokat fázisdiagrammokon mutatjuk be, valamint azokat különböző mikroszerkezet vizsgálatokkal jellemezzük. Az ólommentes forraszanyaggal történő forrasztás után a határfelület vizsgálatát a szerszámok keresztcsiszolatán végeztük el szintén pásztázó elektronmikroszkóppal, a határfelületen keletkező vegyületek összetételének mérésére pedig energiadiszperz spektroszkópiai módszert (EDS) alkalmaztunk. A szerszám geometriájából adódóan annak belső felületén lejátszódó határfelületi reakciókat is ugyanezzel a módszerrel vizsgáltuk. A cikk az elhasználódott szerszám felújítása utáni alkalmazhatóságot is vizsgálja. Az elvégzett vizsgálatokból arra lehet következtetni, hogy az ólommentes forraszanyagok alkalmazásával a szerszám degradációja jelentősen felgyorsult, melynek oka a fúvóka alapanyagának károsodása, vagyis az alapanyag fématomjainak a forraszanyag Sn atomjaival alkotott intermetallikus vegyületfázisának folyamatos vastagodása

Prediction of Earing of Cross‐Rolled Al Sheets from {h00} Pole Figures

The plastic anisotropy of rolled Al sheets is the result of a crystallographic texture. It leads to the formation of uneven cup heights during deep‐drawing, which is called earing. A new, simple and rapid method had been previously developed by the authors to predict earing directly from {h00} pole figures. In the present manuscript, this method is applied to cross‐rolling for the first time. 5056 type aluminum sheets were unidirectionally‐ (conventionally) and cross‐rolled from 4 to ~1 mm thickness in 6 or 12 passes. Earing was predicted from recalculated {200} pole figures obtained after X‐ray diffraction texture measurements. The results were validated by deep‐drawing tests. It is shown that the proposed method predicts the type (locations of ears) and magnitude of earing with satisfactory results. However, a different scaling factor must be used to calculate the magnitude of earing for cross‐rolling than for unidirectional rolling even if all other parameters (including cold rolling, texture measurements, and deep‐drawing) are the same. This is because the cross‐rolled sheets exhibit a similar type but weaker earing compared to the unidirectionally rolled samples

Prediction of earing of aluminium sheets from {h00} pole figures

Earing of deep drawn cups is a result of non-uniform formability caused by crystallographic anisotropy. The prediction of earing is of interest since the rise of the rolling process. Today’s prediction methods are based on theoretical material behaviour functions and apply only within a certain sheet geometry range. In this manuscript, a new and simple method is presented which can be used to calculate the earing of aluminium sheets showing four-fold earing if only texture data is available. The method was applied on 0.3 and 3 mm thick cold rolled 1050 type aluminium sheets subjected to annealing heat treatments for different time intervals to promote recrystallization processes and obtain different earing behaviour. Predicted cup heights are validated with measured data obtained from the performed deep drawn tests. Average earing is also predicted and validated. It is shown that the proposed method is able to predict the type and magnitude of earing with satisfactory results for both 0.3 and 3 mm sheet thicknesses

Hf particles reinforced Cu-Zr-Al amorphous powder produced by milling

This research work dealt with the production of amorphous powder with a nominal composition of (Cu55Zr35Al10)97Hf3 (at%). Combining the mechanical milling and alloying, powder of crystalline Cu-Zr-Al alloy mixed with Hf elemental powder were milled in order to produce a homogenous and amorphous alloy powder. The master alloy and the powders milled for different time were analyzed by X-Ray Analysis (XRD) and Scanning Electron Microscopy (SEM). Particle size distribution and hardness were controlled during milling and at the end of the procedure. The milling caused hafnium dissolution. The 25 h milling time was the optimal to obtain the Hf containing powder with amorphous structure. However, elemental Hf traces with a size below 3 μm were still observed in the powder. After 50 h of milling, such elemental impurities as iron, nickel, chromium originating from milling tools (vial, balls) were detected. © (2013) Trans Tech Publications, Switzerland

Characterization of Ceramic Particle Reinforced Titanium Composite Produced Via Powder Metallurgy

Nowadays, titanium is one of the most popular materials for aeronautical applications due to its good corrosion resistance, formability and strength. In this paper, rutile reinforced titanium matrix composites were produced via powder metallurgy. The steps included high energy ball milling of raw titanium and rutile powders in a planetary ball mill, which was followed by cold-pressing and sintering without external pressure. For the characterization of the milled powders and the sintered composites, scanning electron microscope, X-ray diffraction and compressive strength examinations were carried out. The results showed that the rutile has a strengthening effect on the titanium matrix. 1 wt% rutile increased the compressive strength compared to the raw titanium. Increasing the milling time of the metal matrix decreased the compressive strength values