?url_ver=Z39.88-2004&rft_id=1615021038&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=PENGARUH+HOLDING+TIME+ARTIFICIAL+AGING+TERHADAP+SIFAT+KEKERASAN+DAN+STRUKTUR+MIKRO+Al-2024&rft.creator=Dedy+Rizaldy%2C+1615021038&rft.subject=620+Ilmu+teknik+dan+ilmu+yang+berkaitan&rft.description=Penelitian+ini+bertujuan+untuk+mengetahui+pengaruh+holding+time+artificial+aging+terhadap+sifat+kekerasan+dan+struktur+mikro+Al-2024.+Penelitian+ini+menggunakan+spesimen+berupa+Aluminium+seri+2024+yang+diberi+perlakuan+panas+dengan+suhu+500%C2%B0C+selama+60+menit%2C+kemudian+di+quenching+dengan+media+pendingin+berupa+air.+Selanjutnya+diberi+perlakuan+panas+kembali+dengan+variasi+holding+time++yakni+3+jam%2C+5+jam+dan+7+jam+dengan+temperatur+190%C2%B0C.+Kemudian+spesimen+didinginkan+secara+lambat+dengan+suhu+ruangan.+Hasil+uji+komposisi+kimia+menggunakan+Spectromax+menunjukan+persentase+Al+sebesar+90%2C6%25+dan+Cu+sebesar+5%2C90%25.+Hasil+uji+kekerasan+menggunakan+Rockwell+Hardness+Tester+didapatkan+nilai+kekerasan+tanpa+perlakuan+panas+yang+memiliki+nilai+kekerasan+sebesar+71%2C4+(HRB)%2C+nilai+kekerasan+setelah+diquenching+sebesar+66%2C9+(HRB).+Nilai+kekerasan+tertinggi+terdapat+pada+pemanasan+dengan+variasi+holding+time+5+jam+dengan+temperatur+190%C2%B0C+didapatkan+nilai+kekerasan+sebesar+84%2C6+(HRB)+dimana+nilai+kekerasan+pada+holding+time+5+jam+mengalami++peningkatan+sebesar+8%2C48%25+dari+nilai+kekerasan+bahan+tanpa+perlakuan+panas.+Pengujian+struktur+mikro+didapatkan+hasil+material+Al-Cu+setelah+proses+artificial++aging+pada+holding+time+5+jam+memiliki+fase+presipitat+(%CE%B8)+dengan+jumlah+yang+lebih+banyak+dan+batas+butir+Al-Cu+cenderung+lebih+rapat+dan+teratur.+Hal+ini+berarti+bahwa+pada+bahan+yang+mendapat+perlakuan+artificial+aging+terdapat++endapan++presipitat++atau++terbentuknya++fasa++kedua++yang+menjadi+penyebab+bahan+tersebut+lebih+keras+dan+lebih+baik+sifat+mekanisnya%0D%0A%0D%0AThis+study+aims+to+determine+the+effect+of+holding+time+artificial+aging+on+the+hardness+and+microstructure+of+Al-2024.+This+study+used+a+specimen+in+the+form+of+Aluminum+2024+series+which+was+heat+treated+at+a+temperature+of+500%C2%B0C+for+60+minutes%2C+then+quenched+with+a+cooling+medium+in+the+form+of+water.+Subsequently%2C+it+was+reheated+with+variations+in+holding+time%2C+namely+3+hours%2C+5+hours+and+7+hours+with+a+temperature+of+190%C2%B0C.+Then+the+specimen+is+slowly+cooled+to+room+temperature.+The+results+of+the+chemical+composition+test+using+Spectromax+showed+the+percentage+of+Al+was+90.6%25+and+Cu+was+5.90%25.+The+results+of+the+hardness+test+using+the+Rockwell+Hardness+Tester+obtained+a+hardness+value+without+heat+treatment+which+has+a+hardness+value+of+71.4+(HRB)%2C+a+hardness+value+after+quenching+of+66.9+(HRB).+The+highest+hardness+value+is+found+in+heating+with+a+holding+time+variation+of+5+hours+with+a+temperature+of+190%C2%B0C%2C+the+hardness+value+is+84.6+(HRB)+where+the+hardness+value+at+a+holding+time+of+5+hours+has+increased+by+8.48%25+from+the+hardness+value+of+the+material+without+heat+treatment.+Microstructure+testing+showed+that+the+Al-Cu+material+after+the+artificial+aging+process+at+a+holding+time+of+5+hours+had+a+precipitate+phase+(%CE%B8)+with+a+higher+amount+and+the+Al-Cu+grain+boundaries+tended+to+be+more+dense+and+regular.+This+means+that+the+material+that+has+been+treated+with+artificial+aging+has+precipitated+deposits+or+the+formation+of+a+second+phase+which+causes+the+material+to+be+harder+and+have+better+mechanical+properties.&rft.publisher=FAKULTAS+TEKNIK&rft.date=2022-06-29&rft.type=Skripsi&rft.type=NonPeerReviewed&rft.format=text&rft.identifier=http%3A%2F%2Fdigilib.unila.ac.id%2F65412%2F1%2FABSTRAK.pdf&rft.format=text&rft.identifier=http%3A%2F%2Fdigilib.unila.ac.id%2F65412%2F2%2FSKRIPSI%2520FULL.pdf&rft.format=text&rft.identifier=http%3A%2F%2Fdigilib.unila.ac.id%2F65412%2F3%2FSKRIPSI%2520TANPA%2520PEMBAHASAN.pdf&rft.identifier=++Dedy+Rizaldy%2C+1615021038++(2022)+PENGARUH+HOLDING+TIME+ARTIFICIAL+AGING+TERHADAP+SIFAT+KEKERASAN+DAN+STRUKTUR+MIKRO+Al-2024.++FAKULTAS+TEKNIK%2C+UNIVERSITAS+LAMPUNG.+++++&rft.relation=http%3A%2F%2Fdigilib.unila.ac.id%2F65412%2F