Armour component produced from a 7xxx-series aluminium alloy

Abstract

Described herein are armour components for civil or military vehicles made of high-strength 7XXX-series aluminium alloys requiring ballistic protection. For example, described herein are armour components used for manufacturing armour hulls and add-on appliqués, which are removable panels to be mounted on the external faces of the military vehicles.

1 . An armour component produced from a 7XXX-series aluminium alloy, wherein the aluminium alloy comprises:
 Zn 7.1% to 7.5%,   Mg 1.90% to 2.25%,   Cu 1.3% to 1.8%,   at least 0.05-0.4% of a dispersoid forming element selected from the group consisting of Zr, Sc, V, Hf, Ti, Cr, and Mn,   Ti 0.01% to 0.06%,   Si up to 0.15%,   Fe up to 0.15%,   balance unavoidable impurities and aluminium,   wherein the 7XXX-series aluminium alloy is in the form of a plate having a thickness of 12.7 mm to 76.2 mm;   wherein the 7XXX-series aluminium alloy is over-aged to achieve a combination of:   (i) tensile yield strength in LT-direction >497 MPa,   (ii) ultimate tensile strength in LT-direction >538 MPa,   (iii) elongation in LT-direction >9%, and   (iv) an armour piercing V50 ballistic limit such that meets the requirements of US military spec MIL DTL-32375B (MR) (2021).   
     
     
         2 . The armour component according to  claim 1 , wherein the Zn content is in a range of 7.20% to 7.5%. 
     
     
         3 . The armour component according to  claim 1 , wherein the Zn content is in a range of 7.30% to 7.5%. 
     
     
         4 . The armour component according to  claim 1 , wherein the Zn/Mg ratio is less than 4. 
     
     
         5 . The armour component according to  claim 1 , wherein the Zn/Mg ratio is less than 3.9. 
     
     
         6 . The armour component according to  claim 1 , wherein the dispersoid forming element comprises Zr in a range of 0.06% to 0.15%. 
     
     
         7 . The armour component according to  claim 6 , wherein the Zr content is in a range of 0.08% to 0.14%. 
     
     
         8 . The armour component according to  claim 7 , wherein the Zr content is in a range of 0.09% to 0.13%. 
     
     
         9 . The armour component according to  claim 1 , wherein the Mg content is in a range of 1.9% to 2.25%. 
     
     
         10 . The armour component according to  claim 1 , wherein the Mg content is in a range of 1.95% to 2.20%. 
     
     
         11 . The armour component according to  claim 1 , wherein the over-ageing treatment comprises the following 2-step treatment: 4-12 hours at 110° C.-130° C. followed by 4-20 hours at 140° C.-160° C. 
     
     
         12 . The armour component according to  claim 1 , wherein the over-ageing treatment comprises the following 2-step treatment: 4-12 hours at 110° C.-130° C. followed by 12-20 hours at 140° C.-160° C. 
     
     
         13 . The armour component according to  claim 1 , wherein the over-ageing treatment comprises the following 2-step treatment: 4-12 hours at 110° C.-130° C. followed by 12-18 hours at 140° C.-160° C. 
     
     
         14 . The armour component according to  claim 1 , wherein the 7XXX-series aluminium alloy is manufactured with the following steps:
 a. casting said alloy into an ingot form;   b. homogenizing said ingot;   c. hot working said ingot to obtain a plate;   d. solution heat treating;   e. quenching;   f. stretching to obtain a permanent elongation from 1% to 3%; and   g. over-ageing at least in two steps, the over-ageing treatment corresponding to the following 2-step treatment: 4-12 hours at 110° C.-130° C. followed by 12-20 hours at 140° C.-160° C.   
     
     
         15 . The armour component according to  claim 1 , wherein the 7XXX-series alloy comprises, in wt. %:
 Zn 7.1% to 7.5%,   Mg 1.90% to 2.25%,   Cu 1.3% to 1.8%,   Zr 0.06% to 0.15%,   Ti 0.01% to 0.06%,   Si up to 0.15%   Fe up to 0.15%,   balance unavoidable impurities and aluminium.   
     
     
         16 . The armour component according to  claim 15 , wherein the Si or the Fe content is up to 0.10 wt. %. 
     
     
         17 . The armour component according to  claim 1 , wherein the elongation in LT-direction is >9%. 
     
     
         18 . A method of producing an armour component according to  claim 1 , comprising:
 a. casting said alloy into an ingot form;   b. homogenizing said ingot;   c. hot working said ingot to obtain a plate;   d. solution heat treating;   e. quenching;   f. stretching to obtain a permanent elongation from 1% to 3%; and   g. over-ageing at least in two steps, the over-ageing heat treatment corresponding to the following two-step heat treatment: 4-12 hours at 110° C.-130° C. followed by 12-20 hours at 140° C.-160° C.   
     
     
         19 . The method according to  claim 18 , wherein the over-ageing treatment comprises the following 2-step treatment: 4-12 hours at 110° C.-130° C. followed by 12-20 hours at 140° C.-160° C. 
     
     
         20 . The method according to  claim 18 , wherein the over-ageing treatment comprises the following 2-step treatment: 4-12 hours at 110° C.-130° C. followed by 12-18 hours at 140° C.-160° C.