Effects Of Electric Pulse Modification On The Microstructures And Properties Of Al-Si Piston Alloy

In this paper, in order to study the influence on alloy of different pulse parameters further,the electric pulse was applied into eutectic Al-Si alloy, both in Ti-rich Al-Si piston alloy andNi-rich Al-Si piston alloy melt, to confirm the most superior pulse parameters; meanwhile,heat treatment(T6) was conducted in those alloys responding to pulse parameters sensitivelyto detect the influence on high temperature phases of different aging processes.The results show that in Ti-rich Al-Si piston alloys, pulse frequencies had a greatinfluence on solidification structure and properties, consequently, when the pulse parameterwas300V,8Hz,30s, the phases among alloys distributed uniformly and the microhardnessincreased to143.45HV, increased by14.2%, compared with the non-modified; in Ti-richAl-Si piston alloys, when the pulse parameter was300V,5Hz,30s, Ni-rich high temperaturephases kept even distribution with small sizes, the microhardness and high temperature tensilestrength were advanced to144.56HV and69.88MPa with the rising rates of9.41%and17.5%respectively; finally, the solution and aging treatment was carried out in the alloys withoptimum pulse parameters, in single aging, the microhardness peak value167.62HV could beobtained quickly with the aging parameter of160℃,2h, increased by26.87%at a result ofthe aging time declined significantly with the measure of EPM; n triple aging, the aging peakvalue of microhardness with EPM achieved a increase of4.32HV compared with the samplewithout EPM at160℃、2h+170℃、2h；moreover，in single or triple aging processes，theaging peak value of Ni-rich Al-Si piston alloy was or so the same without EPM, but for themultistage aging alloy with EPM, the heterogeneous precipitation retained a coherent latticerelationship with base phases, the dislocation increased, and the peak value of microhardnessreached a new level of174HV.