Studies of Kinetic Plasticity Effect in High-Speed Steels under Martensite Transformation

In the paper the authors study how the kinetic plasticity effects the temporary and residual stresses formed in instrumental steels when cooling. They also present the results of temporary stresses relaxation. This phenomenon was applied within the temperature range of the martensite transformation to reduce the cold cracking of the surfaced metal. The paper shows that the superplasticity effect emerging at the moment of martensite transformation plays the crucial role in temporary stresses relaxation.

Studies on the Superplasticity Effect in UFA: History and Development (In Memory of Prof. O.A. Kaibyshev)

Prof. O.A. Kaibyshev initiated studies on superplasticity of metals and alloys in Ufa in the 70s-80s of the last century. These studies gave momentum to the development of fundamental and applied studies on superplasticity not only in Russia but in numerous laboratories around the world. This paper highlights the major results of this early work and considers their state-of-the-art and development perspectives for the science and practice of materials superplasticity.

Superplasticity Effect Demonstrated by Gas Forming Hot Bent AA5XXX Sheets into V-Shaped Trough Containing Uneven Concavities

Using low gas pressure as a tool to form metal sheets is certainly feasible. However, the intrinsic flow properties of metal sheet are often a key factor in determining degree of formability, which has not been emphasized or explained well. Most metals, for examples aluminum alloys, can be either superplastic or non-superplastic depending on their original processing history or route (consequently, yielding suitable microstructure) and forming conditions, i.e. mostly temperature and strain rate. This superplasticity effect is clearly demonstrated by gas forming superplastic AA5083 and non-superplastic AA5052 into a V-shaped deep trough containing uneven concavities. The results show the superiority of superplastic material when harsh product standard is required.

Study of the Superplasticity of Copper Alloys Used for Solid Cages

The superplasticity of cast copper alloys used for solid cages is studied by tests of tension and compression in this paper. The results show that cast copper alloys exhibited superplasticity without any pretreatment. Cast aluminum bronze is of superplasticity at the temperatures between 750~800°C with the initial strain rate 1×10-2s-1, the elongation being over 260%. Under the condition of superplasticity compression with the strain rate (1.136~9.091)x10-4s-1 at temperatures between 600~650°C, the cast lead brass presents the superplasticity effect with the maximum flow stress under 2MPa.