Recent developments in high-pressure die-cast magnesium alloys for automotive and future applications

The use of magnesium alloy high pressure die cast(HPDC)components for structural applications,especially in the automotive and transportation industries,where weight reduction is of a great concern,is increasing.As new applications are developing and existing applications are becoming more complex,there is a need for improved properties from magnesium HPDC alloys.This paper reviews the recent developments in HPDC magnesium alloys for transportation applications.Compared to the conventional HPDC magnesium alloys,i.e.AZ91D,AM50A/AM60B and AE44,these new alloys have one or more of the following properties:higher strength,higher ductility,superior high-temperature properties or higher thermal conductivities.In this work,characteristics which are important in product manufacturing or product performance will be evaluated and discussed,including die castability of powertrain component or thin-walled structural component,mechanical properties at elevated temperatures and ductility.Results indicate that these alloys have great potentials to be added to the current magnesium HPDC alloy family and being used in actual automotive and other transport applications.

A study on joining magnesium alloy high pressure die casting components with thread forming fasteners

With tremendous weight saving potential,magnesium alloy high pressure die casting components have been widely used for automotive applications.Magnesium fastening technology is thus becoming increasingly important to design engineers.Joining as-cast holes of magnesium high pressure die casting components with thread forming fasteners provides significant advantages for the assembly process,overall cost benefit and joint integrity.This type of joint is thus preferred for structural applications.Designing the thread forming fasteners with as-cast holes follows the general rules for designing for the machined holes,including carefully designing the variables such as the assembly torque range,the length of thread engagement,the hole diameter and required failure mode.In addition,special attention needs to be paid to the draft angles of the magnesium cast components that are required for the die casting process.In this paper,the effects of above key factors,individually and combined,on the joint performance of thread forming fasteners with as-cast blind holes of AM60B magnesium components are studied.A joint design philosophy was proposed to optimize both joint performance(the prevailing torque,the failure torque and the failure mode)and manufacturing easiness(the hole diameter and corresponding draft angle).The detailed design considerations for as-cast holes of magnesium HPDC are discussed and explained through a hypothetical example.