We have successfully synthesized LaFe11.6Si1.4Hy/Bi composites by cold pressing together with vacuum annealing technology, and systematically investigated the microstructure, magnetism, mechanical performance, and magnetocaloric properties. LaFe11.6Si1.4Hy particles are well surrounded by metallic Bi, without the formation of new phase. The maximum values of the volumetric magnetic entropy change -ΔSM are as high as 51, 49, and 35 mJ/cm3K around 263 K, for the composites with 5, 10 and 15 wt % Bi contents, respectively. The maximum value of the compressive strength for LaFe11.6Si1.4Hy/Bi composites increased continuously from 155 to 358 MPa with increasing Bi content, from 0 to 15 wt %.

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The deformation in superalloy investment casting under thermal-mechanical coupled stress is causing huge waste of materials and energy. Mechanical models of both alloy and shell are essential to predict the deformation of castings accurately. The elastoplastic behavior of superalloy in semi-solid zone is critical to the deformation during solidification. In this paper, the deformation of ring-to-ring castings with Ni-based superalloy K4169 is researched. To obtain the thermal-mechanical behavior of K4169 from solid region to semi-solid zone, physical simulated uniaxial compression is performed. Yield stress and plastic modulus from the measurement are imported into the database for numerical simulation. Different thermal-mechanical models of both alloy and shell are compared. With elastoplastic model for alloy, considering the deformability of shell with elastic model, the accuracy of prediction is within CT4 level, with a maximum error of 0.39mm. The deformation of reaches the minimum when the initial temperature of alloy and shell are 1500℃ and 900℃. The research on semi-solid performance of alloy and thermal-mechanical models can provide theoretical guidance for deformation prediction. The method of this research is promising in dimensional control of castings, and can be transported to dimensional control problems upon solidification process with different kinds of materials and castings.

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