To improve the tensile strength and wear resistance of AlSi10Mg alloys, a novel in situ synthesis method of selective laser melting (SLM) was used to fabricate the Ni-reinforced AlSi10Mg samples. The eutectic Si networks formed around the α-Al crystals by diffusion and transportation via Marangoni convection in the SLM process. Moreover, the XRD and TEM results verified that the Al3Ni nanoparticles were created by the in situ reaction of the Ni and aluminum matrix in the Ni/AlSi10Mg samples. Therefore, the microstructure of the Ni-containing alloys was constituted by the α-Al + Si network + Al3Ni phases. The dislocations accumulated at the continuous Si network boundaries and cannot transmit across the dislocation walls inside the Si network. SEM results revealed that the continuity and size of eutectic Si networks can be tailored by adjusting the Ni contents. Furthermore, the Al matrix also benefited from the Al3Ni nanoparticles against the dislocation movement due to their excellent interfacial bonding. The 3Ni-AlSi10Mg sample exhibited high mechanical properties due to the continuous Si networks and Al3Ni nanoparticles. The tensile strength, elongation, Vickers hardness, friction coefficient, and wear volumes of the 3Ni-AlSi10Mg samples were 401.15 ± 7.97 MPa, 6.23 ± 0.252%, 144.06 ± 0.81 HV, 0.608, 0.11 mm3, respectively, which outperformed the pure AlSi10Mg samples (372.05 ± 1.64 MPa, 5.84 ± 0.269%, 123.22 ± 1.18 HV, 0.66, and 0.135 mm3).

A novel technique for resolver-to-digital conversion (RDC) using principal frequency component S-transform (PFCST) is proposed in this paper. First, the mode envelope of two output signals of the resolver is extracted by PFCST. The envelope extracted by PFCST maintains the same time resolution as the original signal because it performs time-frequency conversion for each sampling point. Then, the quadrant of the resolver is determined by the judgment rule formed by the polarity of the optimum nonzero region of the signals, and the quadrant information is used to correct the arctangent to obtain the accurate rotor position. Finally, the simulations prove that the maximum angle error of the resolver estimated by this method occurs at the quadrant junction but does not exceed one deg., and the experiments are used to verify the effectiveness of the proposed method.

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