Transformation induced plasticity (TRIP) steels is a kind of low-alloying high strength steel with good combination of strength and plasticity. To investigate the material behavior of TRIP steel, the multiscale simulation method was used in this paper. Through the investigation we can see that, multiscale simulation model of TRIP steel can be setup by combining finite element and microscope technology together, and the simulation results agree with the experimental results greatly. Both for uniaxial tension and biaxial tension, the micro stress distribution was unevenly for the difference of material behavior of bainite, ferrite and retained austenite, which create local stress concentration, and for uniaxial tension and biaxial tension, the stress distribution of biaxial tension was relative average, for the boundary condition biaxial tension was a kind of relative even boundary condition, the stress on different direction was balance.

Tensile tests and a cold deep drawing process were developed at room temperature to estimate the stamping formability of AZ31B magnesium alloy sheet. The results show that AZ31B magnesium alloy sheet has poor formability at room temperature with the total elongation of ~ 20%, the yield ratio is about 0.6 and the strain-hardening exponent is 0.18, while the plastic strain ratio is 1.58, and the earing ratio is-0.55.Thus, AZ31B magnesium alloy sheet can not suffer server plastic deformation. It was found that comparatively shallow magnesium alloy cups were satisfactorily formed at room temperature without heating when the punch fillet radius 6mm and the die fillet radius10mm with a 1mm thickness sheet with limit drawing ratio of 1.25.

The microstructure and mechanical responses of the AZ31 with the addition of 1.8% Sn alloys have been studied and compared. Mg alloy sheets were prepared with metal model casting method and subsequent processes by conventional extrusion (CE) and differential speed extrusion (DSE). Mg alloys were hot extruded at 400oC with the extrusion ratio of 101:1. The microstructure of Mg alloy sheets was examined by optical microscopy (OM) and scanning electron microscope (SEM). The results indicated that the grains were dynamically recrystallized after the extrusion process. Moreover, DSE process dramatically enhanced the room temperature ductility of the extruded sheets. It was also presented that the Mg alloy processed by DSE exhibite a classical dimple structure as a result of slip accumulation and ductile tear.

The temperature and its distribution of non-isothermal deep drawing mould is one of the key technologies for magnesium alloy sheet forming process. It exerts a tremendous influence on the service life of deep drawing mould and affects magnesium alloy sheet deep drawing effect. An intelligent PID temperature controller with adaptive ability and self-organization was proposed to control the temperature of non-isothermal deep drawing mould, which included disk-shaped resistance heating coils heating die and blank holder, room temperature water cooling punch of the mould. The temperature control system greatly improved the quality of deep drawing parts of magnesium alloy sheet due to its simple structure, high anti-interference and high controlling precision.

Magnesium alloy, differential temperature drawing, mould structure, surface roughness Abstract. To improve the formability of magnesium alloy sheet, the differential temperature drawing process was presented, and the mould structure of differential temperature drawing process for magnesium alloy was well-designed and fabricated by analyzing the friction and the stress distribution of material in drawing process. With the blank heated to 200-235°C at the flange by inserting heating coils and thermocouples in die and binder and the drawn cup cooled by injecting cooling water into die and punch, the differential temperature drawing process of magnesium alloy sheet was performed successfully and the value of surface roughness Ra1.6um was adopted for punch, Ra0.4um was adopted for die and binder. The result shows that by using the designed mould, the deep drawing performance of AZ31B magnesium alloy can be enhanced obviously and the value of LDR can be increased form 2.1 to 3.05.