低压及差压铸造工艺对ZL114A铝合金铸件组织和性能的影响

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Abstract： The differences in the microstructure and properties of a ZL114A aluminium alloy casting were comparatively investigated using a low pressure casting process and a differential pressure casting process.The results showed that the as-cast microstructure of the alloy under the two casting processes mainly consisted of a -Al matrix，eutectic siliconphase，and thecoarse eutectic phase in theas-cast state was transformed into fine spherical shape after T6 treatment.The average values of tensile strength，yield strength and elongation of the aloy under the differential pressure casting process are 345MPa ，306MPaand 5.3% ，respectively，whichare 6.2% ， 9.3% and 17.8% higher than those of the low pressure casting process.This isdue to the diferential pressure casting process in he liquid metalsolidification processcan providebetter shrinkage capacity，the allymicrostructure ismoredense，the alloy grainrefinement effect is good，and thesecond phase distributioninthe microstructureis more difuse anduniform， the second phase strengthening effectis good.Thefracture mechanismofthealloyinboth ways isamixed tough-britle type，butthe plasticitycharacteristics ofthealloyaremoreobvious underthe diferential pressure casting process.

Keywords： ZL114A alloy; low pressure casting; diferential pressure casting; second phase; mechanical properties

1 序言

ZL114A是典型的亚共晶A1-Si系合金，其流动性好，具有优异的铸造性能[1]，且比强度高、耐腐蚀性能好[2]，因此广泛应用于航空航天、军工领域的大型复杂结构铸件[3，4]。（剩余6886字）