摘 要
鋁合金淬火后，開發(fā)殘余應力會導致后續(xù)機加工中失真。結果會是，機加工零件可能會失去忍受性和不得不冷加工或是重新加工。殘余應力的測量實驗是漫長的、乏味的、和非常昂貴的，例如中子X射線衍射技術的最新發(fā)展。所以，在這項研究中，Al7050鍛造塊淬火以后，使用數(shù)量方法區(qū)預測殘余應力，而且比較預測結果和實驗結果。結果表明了預測值與實驗結果有很好的一致性，最壞的情況下，偏差也只有10-15%。兩種不同的冷加工（壓縮和拉伸）方法常常被用來減少殘余應力。結果比較好顯示了，壓縮和拉伸工藝減少的殘余應力有90%之多。可是單擊壓縮鋁合金方法減少殘余應力比其別低水平的方法更加有效和經(jīng)濟。也研究了彈性模的影響效果。模具偏轉被發(fā)現(xiàn)對減少殘余應力的量從90%降到70%左右。

Residualstressesdevelopedafterquenchingofaluminumalloyscausedistortionduringsubsequentmachining.Asaresult,machinedparts
maybeoutoftoleranceandhavetobecoldworkedorre-machined.Experimentalmeasurementofresidualstressesislengthy,tediousandvery
expensiveevenwiththelatestdevelopmentsinneutronX-raydiffractiontechniques,forinstance.Therefore,inthisstudy,numericaltechniques
areusedtopredictresidualstressesafterquenchingofAl7050forgedblock,andthepredictionswerecomparedwithexperimentalmeasurements.
Theresultsindicatedthatthepredictedvaluesareinverygoodagreementwiththeexperimentalmeasurementswitharound10¨C15%deviationin
theworstcase.Twodifferentmethodsofcoldworking(compressionandstretching)areusedtoreducetheresidualstresses.Thecomparisonof
resultsshowedthatbothcompressionandstretchingprocessesreducedtheresidualstressesmorethan90%.However,single-strikecompression
ofaluminumblocksisfoundtobemoreefcientandcost-effectiveforreducingtheresidualstressestoverylowlevels.Theeffectsofelasticdie
werealsoinvestigated.Diedeectionwasfoundtoaffecttheresidualstressreductioncapabilitynegativelybydecreasingthemagnitudeofstress
reductionfrom90%toabout70%.