CAJ | 학술논문

AZ91HP压铸试样在加热至415℃、保温8h并淬火之后，晶界上离异共晶的粗块状β-Al12Mg17相将溶入基体，形成过饱和的α-Mg固溶体．α-Mg固溶体在人工时效过程中，将发生β-Al12Mg17的非连续和连续的沉淀析出。非连续析出的β-Al12Mg17相在时间和数量上分别先于和大于连续析出的β-Al12Mg17相，其形态和数量都随时效时间变化，对合金的性能影响较大。金相组织观察显示，非连续析出的β-Al12Mg17相首先在晶界形核，开始时呈颗粒状，随后进入块和胞状共存阶段，最后块状的β-Al12Mg17相消失，胞状β-Al12Mg17相不断地向晶内蔓延长大。伴随着β-Al12Mg17相的析出与形态转变过程，AZ91HP性能也随之变化，显示了明显的时效硬化特征。
AZ91HP압주시양재가열지415℃、보온8h병쉬화지후，정계상리이공정적조괴상β-Al12Mg17상장용입기체，형성과포화적α-Mg고용체．α-Mg고용체재인공시효과정중，장발생β-Al12Mg17적비련속화련속적침정석출。비련속석출적β-Al12Mg17상재시간화수량상분별선우화대우련속석출적β-Al12Mg17상，기형태화수량도수시효시간변화，대합금적성능영향교대。금상조직관찰현시，비련속석출적β-Al12Mg17상수선재정계형핵，개시시정과립상，수후진입괴화포상공존계단，최후괴상적β-Al12Mg17상소실，포상β-Al12Mg17상불단지향정내만연장대。반수착β-Al12Mg17상적석출여형태전변과정，AZ91HP성능야수지변화，현시료명현적시효경화특정。
The divorce associate coarse β-Al12Mg17 distributed along the grain boundary will dissolve in the base to form supersaturated solid solution of α-Mg when AZ91HP die casting was dheated to 415℃ for 8 hours and then quenched.The β-Al12Mg17 will precipitated aa scontinuous and non-continuous form during artificial aging.Non-continuous β-Al12Mg17 precipitates earlier and more than continuous β-Al12Mg17.The morphology and amount of non-continuous β-Al12Mg17 changed with aging time and had a great effect on the properties of the alloy.The microstructure observation shown that nucleation of non-continuous β-Al12Mg17 precipitated as the granules along the grain boundaries first,and then it grew up and changed the morphology into the mixture of block and cell,finally the blocks of Al12Mg17 disappeared and the cells extended into the crystal grains.Along with the course of precipitations its morphology changed and the mechanical properties of AZ91HP were also changed and shown obvious precipitation hardening.