Dehai Ping

Atom probe characterization of plate-like precipitates in a Mg–RE–Zn–Zr casting alloy

Abstract This paper demonstrates that the three-dimensional atom probe (3DAP) is capable of characterizing nanoscale precipitates in magnesium alloys. Combined application of 3DAP and transmission electron microscopy reveals that the major precipitate phase in a Mg–2.4wt.%RE–0.4wt.%Zn–0.6wt.%Zr alloy has an ordered G.P. zone structure and a composition of approximately 3.2 at.% Nd, 1.0 at.% Ce and 1.2 at.% Zn.

Microstructural characterization of (Fe0.5Co0.5)88Zr7B4Cu1 nanocrystalline alloys

The distribution of Cu atoms in an Fe44Co44Zr7B4Cu1 nanocrystalline alloy (HITPERM) has been studied by the three-dimensional atom probe technique. Cu atoms do not form clusters prior to the crystallization reaction, and they are partitioned in the remaining amorphous phase after crystallization. A Cu-free Fe44.5Co44.5Zr7B4 alloy has the same microstructure as the alloy with 1% Cu.

Magnetic properties of nanocrystalline FeMCuNbSiB alloys (M: Co, Ni)

Abstract The magnetic properties and microstructure of nanocrystalline FeMCuNbSiB alloys (M: Co, Ni) annealed under a transverse field have been studied. Large induced magnetic anisotropy and good properties in the high frequency range were obtained in Co-rich nanocrystalline FeCo(Cu)NbSiB alloys.

Icosahedral phase formation by the primary crystallization of a Zr-Cu-Pd metallic glass

Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan(Received January 24, 2000)(Accepted March 7, 2000)Keywords: Metallic glasses; Quasicrystal; Melt spinning; Phase transformations; TEMIntroductionZr-based bulk metallic glasses, which exhibit a large supercooled liquid regime,DT

Phase stability and yield stress of Ni-base superalloys containing high Co and Ti

Ni-base superalloys containing high Co (>20 wt pct) and Ti (>5.5 wt pct) were designed in order to study the effects of Co16.9 wt pct Ti addition on phase stability and mechanical property. These new alloys, though they contained high Ti, mainly consisted of γ and γ′ phases. Ni3Ti (η) phase was observed along the grain boundaries in some of the alloys. The formation of η phase was mainly related to the Ti/Al ratio, Ti content, and alloy composition. Tensile and compression tests showed that these new alloys exhibited higher yield stress than that of the baseline alloy, TMW-1(U720LI). The possible strengthening mechanisms were discussed in terms of solid-solution and precipitation strengthening effects by the Co16.9 wt pct Ti additions. Preliminary results show promising trends for the development of new superalloys for turbine disc applications.

Influence of heating rate on the microstructure and magnetic properties of Fe3B/Nd2Fe14B nanocomposite magnets

The influence of heating rate on the microstructure and magnetic properties of the Fe3B/Nd2Fe14B nanocomposite permanent magnet materials produced by the crystallization of the Nd4.5Fe73B18.5Co2Cr2 amorphous alloy has been studied.

Development of New Generation Turbine Disk Superalloys in the HTM21 Project

A new kind of cast & wrought (C&W) Ni-Co base superalloys named as “TMW alloys” was developed recently for compressor and turbine disk of gas turbine engines in the High Temperature Materials 21 Project at the National Institute for Materials Science (NIMS) in Japan. These Ni-Co base superalloys combine the characters of two kinds of γ- γ’ two-phase alloys (Ni-base and Co-base superalloys) and can be fabricated by cheap cast and wrought processing route. The results showed that some of these TMW alloys have superior tensile strength at temperatures up to 750 °C and higher creep resistances up to 725 °C than commercial UDIMET 720 LI alloy.