NBS :

The application of advances in quench factor analysis property prediction to the heat treatment of 7010 aluminium alloy

“…Using Microsoft Excel ® solver the estimated standard deviation (ESD) [7] was minimised for various values of k 2 -k 5 using the initial multiple regression results as candidate values. The ESD is defined as…”

“…This has the result of QFA predicting the properties of alloys, cooled very slowly at temperatures in the upper portion of the curve, approaching zero as σ x /σ max or the fraction of the maximum property values decreases. A solution proposed by Ives et al [7] assumed that σ min was a non-temperature-dependant constant σ 0 , which could be used with the EXCEL solver method and k 2 -k 5 to minimise the ESD. In this case σ 0 was assigned the value of 128 MPa, the annealed Rp 0.2 for 7010.…”

“…To date it has been shown to be very successful as a property prediction technique in the post-quenched properties of both cast and wrought aluminium alloys [2][3][4][5][6] where the maximum property loss did not exceed 10-15%. Recent developments [7,8] have shown that it is now possible to successfully predict properties beyond this limit using modifications to the original quench factor model.…”

Centerline Depletion in Direct-Chill Cast Aluminum Alloys: The Avalanche Effect and Its Consequence for Turbulent Jet Casting

“…The typical location of interest for macrosegregation in DC cast ingots is 26 the centerline region, where up to a 15% difference from the nominal alloy composition can be 27 observed 3,4 . This difference in composition is ultimately deemed responsible for physical 28 property variations in rolled plate products 5,6 . Two mechanisms are traditionally proposed for 29 centerline segregation: shrinkage induced flow, and sedimenting (or floating) grains.…”

Jet Mixing in Direct-Chill Casting of Aluminum: Crater Effects and its Consequence on Centerline Segregation

“…One of the most persistent defects is macrosegregation, or the large-scale inhomogeneity of the concentration of solute elements throughout the casting. Of particular concern in hypoeutectic alloys is the formation of a severely solute-depleted centerline 1 , which is responsible for mechanical property variations in rolled plate products 2,3 . We have recently postulated the dominant role of the accumulation of solute-lean grains on the formation of this centerline region 4 .…”