Shihao Wang

SuperSTEM

Interfacial segregation can modify a substrate's heterogeneous-nucleation potency. In Al alloys inoculated with TiB 2 , for instance, Zr segregation degrades TiB 2 's nucleation potency and causes the loss of grain refinement, a phenomenon termed the Zr-poisoning effect. Here we use grain-refining tests to demonstrate that the addition of Mg can re...

Elemental segregation driven by the reduction of the total Gibbs energy of the system has been widely observed at the melt/substrate interfaces in various Al- and Mg alloys containing different inoculant particles. This study provides experimental observations, analyses, and identifications of the formation of Y-segregation 2DCs at the Mg/MgO inter...

Acting as substrates for heterogeneous nucleation, native oxides in Al–Mg alloys have shown their potential for grain refinement. However, the limited knowledge about the nature of the oxides in Al–Mg alloys impedes the widespread application as native grain refiners. The aim of this work is to comprehensively investigate the native oxides in Al–Mg...

Methanol with 12.5 wt% H2 content is widely considered a liquid hydrogen medium. Taking into account water with 11.1 wt% H2 content, H2 synthesis from the mixture of water and methanol is a promising method for on-demand hydrogen production. We demonstrate an atomic-level catalyst design strategy using the synergy between single atoms and nanodots...

A fine and equiaxed solidification process delivers multidimensional benefits to Mg-alloys, such as improved castability, reduced casting defects, enhanced mechanical properties, increased corrosion resistance and potential for increased recycled contents. Despite extensive research on grain refinement of Mg-alloys in the last few decades, currentl...

During solidification of metallic materials, heterogeneous nucleation occurs on substrates, either endogenous or exogenous. The potency of the substrates for nucleation is mainly dependent upon the atomic arrangements on the substrate surface, which are affected by the lattice misfit between the substrate and the nucleated solid, the surface roughn...

This article provides an overview of high-pressure die casting (HPDC)-related research undertaken at the EPSRC Future LiME Hub between 2015–2022. The project aimed to identify the cause of variability in the tensile ductility of die-cast structures, and to develop novel processing techniques to address this issue. Variability in tensile ductility w...

A quantitative strategy was reported to design and develop Mg-Al-based alloys to achieve high thermal conductivity, in which the specific RE elements can be introduced to reduce the Al concentration in Mg matrix and to suppress the formation of Mg17Al12 phase through the formation of new intermetallic phases. Based on quantitative calculations, the...

Over the past few decades, aluminium (Al) has been considered to be beneficial for castability but detrimental for the creep resistance of magnesium (Mg) alloys. However, an excellent creep resistance has been achieved in a die-cast Mg3.5RE(La,Ce,Nd)1.5GdMnAl alloy, with a super low steady-state creep rate (SCR) of 1.35 × 10⁻¹⁰s⁻¹ at 300°C/50MPa. C...

Al-Si wrought piston alloys can lack properties due to inefficient grain refining. A novel Al-Nb-B grain refiner was introduced some time ago, but has still not been assessed in industry for wrought alloys. This paper describes the first trial of Al-Ni-B addition and its impact on the full-scale manufacturing, structure, and properties of the AA403...

To understand Si precipitation and its influence on mechanical property improvement in high pressure die casting (HPDC) Al9Si3CuFe alloy under direct ageing heat treatment, the precipitates in Al9Si3CuFe alloy containing in-situ MgAl2O4 particles is analyzed via atomic-resolution scanning transmission electron microscopy. It is shown that lath-like...

AlP has been widely used as an effective heterogenous nucleus for primary Si phase in hypereutectic Al-Si alloys, but the morphological correlation between AlP and primary Si is still confusing. In the present work, the morphologies of AlP crystals were studied comprehensively by experimental observation and theorical prediction. It is found that A...

In the present work, a novel low-temperature heat-treatable recycled die-cast Al–Mg alloy was developed by adding Zn into non-heat-treatable Al–5Mg–1.5Fe–0.5Mn alloy. The results showed that Zn additions resulted in the formation of equilibrium phase T-Mg 32 (Al, Zn) 49 under as-cast condition, which can be dissolved into the α-Al matrix at a relat...

The effects of T5 and T6 heat treatment on the microstructural development and mechanical properties of newly developed die-cast Al-xCu-2.2%Si-1.1%Mg (x=5, 6.6 and 10.6, in wt%) alloys were investigated. After T5 heat treatment to peak hardness, the main precipitates changes from β’’ in Al5Cu to β’’ and θ’ in Al6.6Cu and then to θ’ and Q’’-type pre...

The global carbon emission reduction strongly requires high strength lightweight die-cast aluminium alloys in industry. Here die-cast AlSiMgMn–TiB2 composites with advanced mechanical performance were fabricated by the implantation of TiB2 nanoparticles. Super vacuum assisted high pressure die casting was applied to enable the T6 heat treatment of...

The development of lightweight magnesium (Mg) alloys capable of operating at elevated temperatures of 200-300 °C and the ability of using high pressure die casting for high-volume manufacturing are the most advanced developments in manufacturing critical parts for internal combustion engines used in power tools. Here we report the microstructure an...

High as-cast strength die-cast AlSi9Cu2Mg alloy was achieved with industrially acceptable ductility, via the addition of titanium diboride nanoparticles. The main intermetallic compounds in the die-cast AlSi9Cu2Mg alloy were identified as qeAl 2 Cu and QeAl 5 Cu 2 Mg 8 Si 6 phases. The Fe-rich compound formed in the present die-cast alloy with a hi...

To reveal the influence of porosity on the variability in mechanical properties of HPDC Al alloys, micro computed tomography was employed to investigate the morphology and 3D distribution of porosity in the tensile samples. Experimental results show that the variability in mechanical properties of HPDC AlSi7MgMn alloy is related to the pore size an...

Native MgO particles in Mg-alloy melts have been recently exploited as potential substrates for heterogeneous nucleation during solidification, leading to significant grain refinement of various Mg-alloys. However, our current knowledge of the nature of the native MgO particles is still limited. In this work, we study both the physical and chemical...

The global carbon emission reduction strongly requires high strength lightweight die-cast aluminium alloys in industry. Here die-cast AlSiMgMn–TiB2 composites with advanced mechanical performance were fabricated by the implantation of TiB2 nanoparticles. Super vacuum assisted high pressure die casting was applied to enable the T6 heat treatment of...

It has been reported that native MgO particles in Mg alloy melts can act as heterogeneous nucleation substrates such that grain refinement of Mg alloys is achieved. A recent study showed the addition of Ca, combined with the native MgO particles, significantly improves grain refinement of Mg and its alloys. However, the mechanism underlying the gra...

It has been reported that native MgO particles in Mg alloy melts can act as heterogeneous nucleation substrates such that grain refinement of Mg alloys is achieved. A recent study showed the addition of Ca, combined with the native MgO particles, significantly improves grain refinement of Mg and its alloys. However, the mechanism underlying the gra...

To improve the properties of high pressure die cast Al9Si3Cu alloy, melt treatment via high shear was employed to form fine in-situ MgAl2O4 particles which act as potential nuclei to refine α-Al grains whilst providing reinforcement to enhance the tensile strengths of the alloy. Experimental results showed that the naturally formed MgAl2O4 particle...

The structural lightweight in automotive and other industries motivates the usage of high strength die-cast aluminium alloys. However, the improvements of die-cast aluminium alloys are struggling limited by conventional micro alloying, and the improved yield strengths are still in the low level of 180-190 MPa. Here, high performance die-cast AlSiMg...

A new strategy through controlling the aggregation states of alloying elements before cold-rolling is proposed to tune the nano-precipitation in Al alloys processed by combining deformation and aging. A considerable improvement in strength and good ductility is achieved in Al-Mg-Si-Cu alloy by our approach, which is applicable to many precipitation...

The mechanical properties of an Al-Mg-Si-T5 and Al-Zn-Mg-T4 dissimilar weld joint were tested through hardness test, tensile test and fatigue test, and the microstructure was investigated by scanning electron microcopy (SEM), backscattered-electron diffraction (EBSD), energy dispersive spectrometer (EDS) and transmission electron microscopy (TEM)....

Although AlMgSi (6000-series) are generally considered to have better corrosion resistance than other aluminum alloys, it may introduce susceptibility to intergranular corrosion (IGC) by some factors, for instance, improper thermo-mechanical treatment and high Cu content. So the T78 treatment has been designed to desensitize it to IGC. In this pape...